The Shoulder Pain That Was Not an Injury

Seek emergency care now for shoulder or arm pain with chest tightness, sweating, nausea, or breathlessness. Also seek emergency care for shoulder-tip pain with severe abdominal pain, dizziness, or fainting.

Book an appointment sooner if any of these apply.

• There was no injury at all.
• The pain wakes you consistently at night.
• It is getting worse each week rather than settling.
• Any of the neurological or eye features below have appeared.

Pain that followed a clear strain, and that changes with position and movement, can reasonably be managed with activity changes and physiotherapy. Give it four to six weeks before reassessment. If you have already had six weeks of treatment with no improvement, ask specifically whether imaging should include the chest, not only the shoulder.

The overwhelming majority of shoulder pain is mechanical. Nearly all of it comes from a short list: rotator cuff tendinopathy and tears, subacromial impingement, adhesive capsulitis (frozen shoulder), osteoarthritis, and pain referred from an arthritic neck. These share a recognizable pattern. The pain links to particular movements or positions. A clinician can reproduce it by moving your arm. It is often tender to press. It tends to improve over weeks with rest, activity changes, and physiotherapy.

Cancer is an uncommon cause of shoulder pain. It appears on this list because when it does cause shoulder pain, the pain behaves differently. That difference is learnable.

Structures that have nothing to do with the shoulder joint can send pain there.

The diaphragm shares nerve supply with the skin over the tip of the shoulder. So irritation beneath it can cause shoulder pain with an entirely normal shoulder exam. This includes irritation from the liver, gallbladder, spleen, an abscess, or the lining of the lung. Heart problems refer pain to the left shoulder and arm, usually with chest heaviness, sweating, or breathlessness.

The pattern most relevant here comes from the very top of the lung. Tumors in that position, known as Pancoast or superior sulcus tumors, make up about 3% to 5% of lung cancers. They typically lack the usual lung cancer symptoms: there is often no cough and no coughing of blood. Shoulder pain is the presenting complaint in up to 96% of cases. That is exactly why these are so often treated first as rotator cuff problems, cervical disc disease, or frozen shoulder. Diagnostic delays of five to ten months are documented.

Consider raising these specifically if they apply to you.

• No injury, strain, or unaccustomed activity preceded the pain.
• The pain is not reproduced by moving the shoulder, and moving it freely does not make it worse.
• Pain wakes you at night and does not settle whatever position you take.
• The pain is steadily worsening over weeks rather than fluctuating.
• Six weeks of physiotherapy or rest have produced no change at all.
• Pain radiates to the shoulder blade, armpit, or down the inner side of the arm.
• Numbness or tingling in the ring and little fingers, or weakness and wasting of the small muscles of the hand.
• A drooping eyelid with a smaller pupil on the same side, or reduced sweating on that side of the face.
• Hoarseness, breathlessness, unexplained weight loss, or a smoking history.

The last two bullets together describe a combination clinicians are taught to take seriously. That combination is shoulder pain, plus hand symptoms, plus eye changes, all on the same side.

A thorough assessment examines the shoulder, the neck, and the chest. It includes a neurological exam of the arm and hand. Reproducing the pain with shoulder movement points strongly toward a joint or tendon cause. Being unable to reproduce it is itself informative.

Imaging usually starts with a plain shoulder X-ray. When the history does not fit an injury, a chest X-ray is added. Lesions at the lung apex are notoriously easy to miss on X-ray because of overlying shadows. CT of the chest is more reliable. MRI of the thoracic inlet and brachial plexus (the nerve network near the collarbone) is the most sensitive test. Your team orders it when they suspect a superior sulcus tumor or nerve root involvement. Blood tests may be added when infection or inflammatory disease is possible. Ultrasound or MRI of the shoulder itself assesses rotator cuff structures.

• StatPearls: Pancoast Syndrome.
• NCI: Non-Small Cell Lung Cancer Treatment (PDQ).
• NICE NG12: recommendations organised by site of cancer.
• EyeWiki (American Academy of Ophthalmology): Horner Syndrome.