Pain from the shoulder: the most common cause
The rotator cuff tendons and the subacromial bursa refer pain to the outer upper arm, often around the deltoid insertion halfway down the arm. People often think the problem is in the arm muscle, but the source is the shoulder.
Typical features are pain lifting the arm out to the side or overhead, reaching behind your back, putting on a coat and lying on that side. See shoulder bursitis and frozen shoulder.
Deltoid pain and muscle strain
- Overuse in the gym, especially overhead pressing and lateral raises.
- Repetitive lifting or carrying at work.
- Delayed onset muscle soreness after new exercise.
- Injection site soreness after vaccines.
Muscle strains improve within days to a few weeks with relative rest and gradual return to activity.
Biceps tendon problems
Pain at the front of the shoulder and upper arm, worse with lifting, carrying and bending the elbow against resistance, may come from biceps tendinopathy. A sudden pop with bruising and a bulge in the arm (“Popeye” sign) suggests a ruptured biceps tendon.
See bicep tendonitis and ruptured biceps.
Nerve pain from the neck
A trapped nerve in the neck causes pain that travels from the neck or shoulder blade down the arm, often with burning, tingling, numbness or weakness in a specific part of the arm or hand. It may worsen when looking up or turning the head towards the painful side.
Other causes
- Fractures: of the humerus after falls, especially in older adults with osteoporosis.
- Thoracic outlet syndrome: arm pain, tingling and heaviness when lifting the arms.
- Blood clots: swelling, heaviness and redness of the arm, rare.
- Infections and bone conditions: rare, with fever or night pain.
- Heart: angina or heart attack can cause arm pain.
When arm pain could be your heart
Heart attack pain is usually in the chest but can spread to or be felt mainly in the arms, especially the left, jaw, neck or back. It may come with breathlessness, sweating, nausea, light-headedness or a sense of dread. Call emergency services immediately if these symptoms occur. Symptoms can be milder or atypical in women, older adults and people with diabetes.
How the source is found
A physiotherapist or doctor asks how the pain started, what makes it worse and whether there are nerve symptoms, then examines the neck, shoulder, arm and elbow. Imaging is not usually needed, but ultrasound, X-ray or MRI can help in some cases, and nerve studies are used for persistent nerve symptoms.
What helps
- Relative rest from aggravating activities, without stopping using the arm.
- Ice or heat, whichever feels better.
- Simple painkillers if appropriate.
- Sleeping with a pillow supporting the arm.
- Gentle movement to avoid stiffness.
Exercises
- Pendulum swings for an irritable shoulder.
- Isometric shoulder exercises against a wall.
- Rotator cuff strengthening with a band; see rotator cuff exercises.
- Neck mobility for nerve-related pain, as guided by a physiotherapist.
- Gradual return to lifting and gym exercises.
Why upper arm pain is often worse at night
Shoulder tendon and bursa problems often ache more at night, because lying on the shoulder compresses the painful tissues and lying flat changes the position of the joint. Sleeping on the other side with a pillow hugged in front of you, or on your back with a small pillow under the painful arm, often helps.
See shoulder pain from sleeping on your side. Night pain that is constant and unrelated to position, especially with weight loss or fever, should be checked.
When to seek help
- Arm pain with chest pain, breathlessness, sweating or nausea: call emergency services.
- Deformity or severe pain after a fall.
- A pop and bulge in the arm after lifting.
- Progressive weakness or numbness in the arm or hand.
- Swelling and redness of the whole arm.
- Fever, night pain or unexplained weight loss.
Key points to remember
- Upper arm pain often comes from the shoulder rotator cuff or the neck.
- Muscle strains and biceps tendon problems are other common causes.
- Most causes improve with relative rest and progressive exercises.
- Arm pain with chest symptoms is an emergency.
Questions about upper arm pain
These answers are general information and do not replace an examination or individual medical advice.
Why does my upper arm hurt without injury?
Rotator cuff problems and trapped nerves in the neck are common causes.
Why does my upper arm hurt at night?
Shoulder problems such as rotator cuff tendinopathy often worsen at night and when lying on that side.
Is left upper arm pain a sign of a heart attack?
It can be, especially with chest pain, breathlessness or sweating. Seek emergency help.
What does deltoid pain mean?
Often shoulder tendon pain felt in the deltoid area, or a muscle strain.
How long does upper arm pain last?
Strains improve in days to weeks; tendon problems can take 6 to 12 weeks with exercise.
Can a pinched nerve cause upper arm pain?
Yes. A trapped nerve in the neck can cause arm pain with tingling or numbness.
Should I rest or exercise upper arm pain?
Reduce painful activities but keep moving gently; progressive exercise helps recovery.
Can sleeping position cause upper arm pain?
Yes. Lying on the affected shoulder can aggravate tendon pain felt in the upper arm.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.