Why Does My Shoulder Hurt When I Lift My Arm?

“My shoulder hurts when I lift my arm” — it is one of the sentences heard most often in physiotherapy. This pain, appearing as you reach for a shelf, brush your hair or pull on a t-shirt, makes daily life surprisingly difficult. But there is an important truth here: this is not one disease, but a shared symptom of many quite different conditions. This article works through the possible causes of shoulder pain when lifting the arm, which one may fit you, and what the right step is — like a road map.

Why is the shoulder such a troublesome joint?

The shoulder has the widest range of movement of any joint in the body — and that flexibility comes with a trade-off. In fact, the shoulder is not even a single joint; it is a system of four separate joints working together. The main ball-and-socket joint where the arm bone sits against the shoulder blade (glenohumeral), the small joint right at the top of the shoulder (acromioclavicular), the joint where the collarbone meets the trunk (sternoclavicular), and the structure by which the shoulder blade glides over the ribcage (scapulothoracic)… Lifting your arm above your head requires all four to move in the right sequence and in harmony.

And here is the key point: when there is a hitch anywhere in that harmony — in a tendon, in a joint, or in the timing of the shoulder blade — lifting the arm becomes painful. This is why “shoulder pain” is not one diagnosis but a shared complaint that can arise from different structures. And the right solution comes from understanding exactly which structure is affected.

Pain when lifting: possible causes

The presentations below are the most common causes of shoulder pain when lifting the arm. Where, when and how the pain appears gives clues about which one may be involved.

Pain within a certain range of the movement (the painful arc). Pain that appears at roughly mid-height as you lift the arm out to the side, and eases as the arm goes higher, most often points to the presentation known as shoulder impingement. It is associated with irritation of the tendons beneath the roof of the shoulder as the arm lifts. For the details, see Shoulder Impingement Syndrome.

Pain together with weakness. If lifting the arm brings both pain and a marked loss of strength (struggling to hold the arm up, being unable to lift something), the problem may lie in the group of tendons called the rotator cuff. The article on Rotator Cuff Tears covers this presentation.

Pain plus steadily increasing stiffness. If the arm is not just painful but will not move in several directions — even when someone else tries to lift it — it may be frozen shoulder. The article How Long Does Frozen Shoulder Last? walks through this process.

Pinpoint pain right at the top. If the pain sits right at the top of the shoulder, at a spot precise enough to point to with a finger, and worsens when you lift the arm fully overhead or bring it across the front of your body towards the opposite shoulder, the small joint at the top of the shoulder (the acromioclavicular joint) may be responsible. The cause is most often wear over the years, or a fall or blow.

Numbness or tingling spreading into the arm or hand. If the pain comes with numbness, tingling or weakness spreading towards the arm or hand, and changes with neck movements, the source is likely to be the neck rather than the shoulder. The article Can Your Shoulder Pain Actually Come from Your Neck? examines this.

Pain that worsens particularly at night. If the pain is bearable during the day but becomes prominent at night and makes lying on that side difficult, night pain has reasons of its own. We cover them in Why Does Shoulder Pain Get Worse at Night?.

Reading the clues of the pain

As you can see, the “character” of the pain carries strong clues about which structure is affected. Where the pain sits (at the top, at the front-outer side, spreading into the arm), when it appears (at a certain angle, at night, with every movement), and whether other symptoms come with it (weakness, stiffness, numbness) — all of these form a picture. Even so, these clues point the way; they do not settle the question on their own, because presentations sometimes overlap and similar symptoms can arise from different causes. The definitive distinction becomes clear through a physiotherapist taking your history and assessing the arm by moving it in specific directions.

The common thread, whatever the cause

All of these presentations share one thing: in almost every one of them, the first and most important step is a proper assessment and a physiotherapy programme built on it. The assessment establishes which structure the pain is coming from; physiotherapy then brings together manual therapy, movement and strengthening work as the situation requires — reducing the pain and restoring the shoulder’s healthy movement. What matters is not getting stuck on a generic label like “shoulder pain”, but finding the actual cause behind that pain and addressing it properly. For an overview of these shoulder structures and the treatment approach, see the Shoulder Problems page.

When is earlier assessment needed?

Most shoulder pain improves with time and the right approach; but some signs call for an earlier and more careful assessment: severe pain that starts after a sudden trauma (a fall, a blow), weakness marked enough that you cannot lift or hold the arm at all, progressive loss of sensation spreading into the arm, or symptoms affecting both arms at once. These situations are uncommon, but it is important to have them assessed promptly.

References

1. Shoulder Complex / Scapulohumeral Rhythm — Physiopedia.
2. Acromioclavicular Joint — Physiopedia.
3. 3-Dimensional Shoulder Complex Kinematics in Shoulder Pain — JOSPT/PMC.