Why your shoulder hurts when you reach overhead (and what to do about it)

By Flora Muijzer | Physiotherapist & Sports Performance Specialist

Reading time: approx. 9 minutes

Shoulder pain is one of the most common reasons people come to see me, and one of the most frustrating, because it tends to creep up gradually rather than arriving with a clear, definable incident. You notice it first reaching for something on a high shelf. Then it's there during your swimming stroke, your tennis serve, or when you put on a jacket. Before long, you're sleeping on one side to avoid it and wondering how something so ordinary became so limiting.

The good news is that most shoulder pain — including the kind that's been grumbling for months — responds very well to the right approach. But first, it helps to understand what's actually going on.

Do you have shoulder pain when reaching overhead?

The shoulder is built for mobility, not stability

To understand why shoulders are vulnerable, it helps to appreciate what makes them remarkable. The shoulder joint (glenohumeral joint) is a ball-and-socket joint, but unlike the hip, which has a deep socket that provides natural stability, the shoulder socket is remarkably shallow. This is what gives you the extraordinary range of motion to reach in almost any direction. The trade-off is that it relies heavily on the surrounding muscles, tendons, and soft tissue structures to hold everything in place.

The rotator cuff — a group of four muscles that wrap around the shoulder joint — is the primary stabilising system. These muscles don't just move the arm; their main job is to keep the ball of the humerus centred in the socket throughout every movement. When the rotator cuff isn't functioning well, the mechanics of the entire shoulder change. And that's when things start to hurt.

What is shoulder impingement?

"Shoulder impingement" is a term you'll hear often, and it describes a situation where the tendons of the rotator cuff, most often the supraspinatus tendon, are being compressed between the ball of the humerus and the bony arch above it (the acromion). This causes pain, usually felt on the outer side or front of the shoulder, that's typically worst when reaching overhead, across the body, or behind the back.

There's a painful arc, often roughly between 60 and 120 degrees of arm elevation, that's characteristic of impingement-related pain. Below and above that arc, things are often more comfortable.

It's worth knowing that impingement isn't quite the right framing for what most people experience. The modern understanding has shifted away from the idea of mechanical pinching as the primary problem, and towards load management and tendon irritation as the more accurate explanation. The tendon isn't being crushed — it's being repeatedly irritated by movement patterns that place too much demand on an under-prepared structure. This matters because it changes how we should treat it.

Common causes I see in my clinic

Rotator Cuff Weakness

The most consistent finding in people with shoulder impingement is weakness in the rotator cuff itself, particularly the external rotators and the lower fibres of trapezius and serratus anterior, which are responsible for controlling the shoulder blade. When these muscles don't fire properly or can't handle the load, the mechanics of the shoulder change and the rotator cuff tendons end up working in a compromised position.

Poor Scapular Control

The shoulder blade (scapula) is the foundation from which the rotator cuff works. If it's not moving and positioning correctly, tilting, rotating, and elevating in the right sequence as you raise your arm, the space available for the tendons narrows and the muscle timing is off. Scapular control is something most people have never thought about, but it's often central to resolving shoulder problems.

A Sudden Spike in Training Load

This one appears especially in summer, when people return to swimming, overhead gym work, or racket sports after a long break. The rotator cuff tendons, like all tendons, adapt slowly. Increasing volume or intensity faster than the tendons can adapt is one of the most common triggers for shoulder pain in active people.

Prolonged Desk Posture

Hours of sitting with the shoulders rounded forward changes the resting position of the shoulder blade and alters how the rotator cuff has to work. Over time, this contributes to the muscle imbalances that set the stage for impingement-type pain. The desk isn't the direct cause, but it creates conditions where the shoulder becomes more vulnerable.

What doesn't work (and why people keep doing it anyway)

Resting Completely

Painful shoulder? Rest it, surely. The problem is that tendons and muscles respond to load — they need progressive stimulus to remodel and strengthen. Complete rest removes that stimulus, and the shoulder returns to activity still unprepared for the demands placed on it. A short period of relative rest to calm acute inflammation makes sense, but extended avoidance does not.

Relying on Anti-Inflammatories Alone

NSAIDs can help manage pain in the short term, which has value — you can sleep better and keep moving. But they don't address the underlying mechanics. Used alone without rehabilitation, they're a temporary patch on a structural problem.

Cortisone Injections as a First Resort

Corticosteroid injections are sometimes appropriate, particularly when pain is severe and preventing engagement with rehabilitation. But the evidence suggests they should be used as an enabler of rehab, not a substitute for it. Multiple injections into a tendon over time are associated with poorer long-term outcomes. If you've been offered one, it's worth asking whether a structured physiotherapy programme has been tried first.

What actually works

Targeted Rotator Cuff and Scapular Strengthening

This is the cornerstone of almost every shoulder rehabilitation programme I run, and the research backs it strongly. The goal isn't to build big shoulder muscles — it's to restore normal timing, coordination, and strength in the structures that stabilise the joint.

Exercises I commonly use include:

• Side-lying external rotation: a deceptively simple but powerful exercise for the infraspinatus and teres minor, two of the most frequently underworked rotator cuff muscles

• Band pull-aparts and face pulls: to activate the posterior rotator cuff and retrain the lower trapezius

• Wall slides and serratus push-up plus: to improve scapular control and the upward rotation pattern essential for overhead movement

• Isometric holds in pain-free positions: particularly useful early on when loading the tendon through range provokes too much pain

The key is starting within a pain-free or low-pain range and building gradually. Forcing through sharp pain early in rehab consistently delays recovery.

Restoring Range of Motion

Stiffness in the shoulder joint, particularly in internal rotation and posterior capsule flexibility, is common in people with chronic shoulder pain and contributes to the problem by altering joint mechanics. Gentle mobility work, including the cross-body stretch and sleeper stretch, can help restore this range over time. These should feel like a tolerable stretch, not pain.

Addressing the Whole Chain

The shoulder doesn't operate in isolation. Thoracic spine stiffness — the mid-back becoming rigid from too much sitting — restricts how well the shoulder blade can move, which directly affects the shoulder joint above it. I often spend as much time working on thoracic mobility in patients with shoulder pain as I do on the shoulder itself, because the results are frequently dramatic.

Similarly, in throwing and racket sports, shoulder injuries often have a contribution from the lower body. Inadequate hip rotation and trunk rotation mean the arm has to generate more force independently, increasing the load on the shoulder.

Load Management

If you're training with a shoulder that's irritable, the answer isn't necessarily to stop everything — it's to modify intelligently. This might mean temporarily reducing volume, avoiding specific aggravating movements (often internal rotation under load, or behind-the-head movements), and replacing those with pain-free alternatives that keep you training without making things worse.

A gradual return to overhead loading, guided by pain response, is usually achievable far sooner than most people expect.

Do you have full shoulder mobility?

When to see someone

Shoulder pain has a wide spectrum of severity, and not all of it requires urgent attention. But some situations do warrant prompt assessment:

• Pain that's been present for more than six weeks without improvement

• Significant weakness in the arm, particularly difficulty lifting the arm away from your side

• Pain at rest or at night that's severe and doesn't settle with position changes

• A history of trauma (fall on an outstretched hand, direct impact) with sudden loss of strength

• Any sign of joint instability, a feeling of the shoulder slipping or being about to come out
  

The last two in particular should be assessed promptly, as significant rotator cuff tears and shoulder instability need different management from impingement.

For the more common presentation — pain building gradually over weeks, aggravated by overhead and behind-the-back movements, settling with rest — the evidence strongly supports physiotherapy-led rehabilitation as the most effective intervention.

How long does it take?

This is the question I'm asked most, and the honest answer is: it depends. Mild to moderate impingement-related pain, addressed early with a good rehabilitation programme, often improves significantly within six to eight weeks. Chronic presentations — pain that's been present for six months or longer, with significant strength deficits — typically take three to six months to fully resolve.

The sooner you start addressing the underlying mechanics rather than just managing pain, the faster and more completely you tend to recover. The shoulder wants to function well. It just needs the right conditions to get there.

The bottom line

Shoulder pain when reaching overhead is common, but it's not something you have to simply live with. In the vast majority of cases, a structured approach targeting rotator cuff strength, scapular control, and load management produces meaningful, lasting improvement, without surgery and often without injections.

If your shoulder has been limiting you, now is a good time to get it properly assessed. Summer sport is coming, and you don't want to spend it on the sidelines.

Flora Muijzer is a physiotherapist and sports performance specialist at Physio Flora. If you're dealing with shoulder pain or want a structured plan to get back to overhead sport and training, get in touch to book an assessment.

Physio Flora is based in Riviera del Sol & Marbella, serving patients across Marbella, San Pedro de Alcantara, Benahavis, Estepona, Elviria, Calahonda, Mijas, Fuengirola, Benalmádena, and the wider Costa del Sol.

Book your appointment directly online: https://physioflora.janeapp.com

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