Pain in the left arm and shoulder is common, ranging from a minor annoyance to a serious health problem. While often stemming from musculoskeletal issues, this pain can sometimes indicate urgent underlying conditions. Understanding its causes helps determine when medical attention is needed.
Common Musculoskeletal Causes
Left arm and shoulder pain often stems from issues within muscles, tendons, ligaments, and joints. Muscle strains occur due to overuse or sudden movements, causing localized tenderness and pain that improves with rest. This pain typically feels like a dull ache and can be accompanied by stiffness.
Rotator cuff injuries, involving the muscles and tendons stabilizing the shoulder joint, are another common source of discomfort. These injuries cause a dull ache deep in the shoulder, worsening at night, and may cause difficulty with overhead movements or reaching behind the back. They often develop from wear and tear, repetitive overhead activities, or sudden trauma.
Bursitis, inflammation of the fluid-filled sacs (bursae) cushioning joints, can also cause shoulder pain. It results from irritation or damage to the bursae, often due to injuries, overuse, or repetitive motions like throwing or heavy lifting. Symptoms include pain, swelling, stiffness, and a reduced range of motion, with discomfort often aggravated by overhead activities and sleeping on the affected side.
Tendinitis, inflammation of other tendons in the shoulder or arm, often arises from a pinched tendon. This condition is common in sports requiring repetitive overhead arm movements, such as baseball or swimming. Symptoms include pain, weakness, or soreness in the shoulder, sometimes radiating down the arm, and can include pain at night or difficulty holding the arm in certain positions.
Osteoarthritis, a degenerative joint disease where cartilage wears away, can also affect the shoulder. It causes pain and stiffness around the shoulder joint and upper arm, often worse with movement or at the end of the day, and may produce grinding or crackling sounds (crepitus) during movement.
Nerve-Related Pain
Pain in the left arm and shoulder can also originate from nerve compression or irritation, often higher in the neck or upper spine, radiating downwards. Cervical radiculopathy, a pinched nerve in the neck, occurs when a nerve root in the cervical spine is compressed by a herniated disc or bone spur. This compression causes pain, numbness, tingling, or weakness that travels from the neck into the shoulder, arm, or hand. Nerve pain differs from muscle pain, often described as sharp, shooting, or burning sensations, sometimes accompanied by tingling or numbness, rather than a dull ache.
Thoracic Outlet Syndrome (TOS) is another less common nerve compression issue affecting the arm and shoulder. TOS involves the compression of nerves or blood vessels in the space between the collarbone and the first rib. Nerve compression in TOS causes pain, numbness, tingling, or weakness in the arm and hand. Unlike localized muscle pain, nerve pain tends to radiate along the path of the affected nerve.
Cardiac and Other Urgent Concerns
Left arm and shoulder pain can signal serious, potentially life-threatening conditions. A heart attack can present with pain or discomfort in the left arm or shoulder. It is often accompanied by chest pressure, tightness, squeezing, shortness of breath, sweating, nausea, or dizziness. Arm pain can be the only symptom, and women may experience more subtle signs, including pain in the back, neck, or jaw, in addition to arm pain.
Angina, chest pain from reduced blood flow to the heart, can also radiate to the left arm and shoulder. Angina pain is triggered by physical exertion or emotional stress and subsides with rest. It may feel like pressure, squeezing, or tightness in the chest, and can extend to the shoulders, neck, jaw, or back.
Other serious conditions include: An aortic dissection, a tear in the inner layer of the body’s main artery (aorta), causes sudden, severe pain often described as a tearing or ripping sensation. It typically starts in the chest or upper back and can spread to the neck, arms, or legs. Pancoast tumors, a rare lung cancer in the uppermost part of the lung, can cause severe shoulder pain radiating down the arm. These tumors often press on nerves in the shoulder and arm, leading to pain, weakness, numbness, or tingling.
When to Consult a Doctor
Seek medical evaluation for left arm and shoulder pain when necessary. Immediate emergency medical attention is necessary if pain is sudden and severe, or accompanied by “red flag” symptoms like chest pressure, shortness of breath, sweating, nausea, or dizziness. Pain after a significant injury, or associated with a visible deformity or inability to move the shoulder, also requires prompt care.
For less acute situations, consult a doctor if pain persists for several days, worsens, or significantly interferes with daily activities. Other signs warranting medical advice include swelling, redness, warmth around the joint, progressive arm weakness, or numbness and tingling. A medical professional can diagnose the cause and recommend a treatment plan.