Pain in the left shoulder is a common experience, often prompting concern due to its causes. This discomfort can arise from a range of conditions, some being minor and easily manageable, while others may signal more serious underlying health issues. Understanding the various reasons behind left shoulder pain can help individuals interpret their symptoms and seek appropriate care.
Direct Shoulder Issues: Common Musculoskeletal Causes
Many instances of left shoulder pain stem from problems directly within the shoulder joint or its surrounding tissues. The rotator cuff, muscles and tendons, provides stability and arm movement. Injuries such as tendinitis, an inflammation of these tendons, often result from repetitive overhead activities, causing a dull ache that worsens with specific movements. Tears in the rotator cuff tendons, from trauma or gradual development, lead to significant pain, weakness, and difficulty lifting the arm.
Bursitis is another frequent cause of shoulder pain, involving the inflammation of a bursa, a fluid-filled sac cushioning the joint. When the bursa becomes inflamed from overuse or repetitive motion, it causes localized pain and tenderness, particularly when pressing on the affected area or moving the arm. This inflammation can restrict movement and make sleeping on the affected side uncomfortable.
Osteoarthritis, a degenerative joint disease, can affect the shoulder, leading to a gradual breakdown of the cartilage that cushions the bones. This “wear-and-tear” process causes pain, stiffness, and a grinding sensation as bones rub against each other. As the condition progresses, the range of motion in the shoulder may decrease, impacting daily activities.
Frozen shoulder, or adhesive capsulitis, is characterized by progressive stiffness and pain in the shoulder joint. It develops when the joint capsule thickens and tightens, restricting movement. This process often occurs in painful, stiffening, and thawing stages. Muscle strains or sprains in the shoulder area, from overstretching or sudden injury, cause localized pain and tenderness. These injuries involve the tearing of muscle fibers or ligaments, leading to immediate discomfort that may worsen with movement or pressure.
Referred Pain: Signals from Other Body Parts
Pain felt in the left shoulder sometimes originates from organs located elsewhere in the body, known as referred pain. This occurs because nerves supplying internal organs and those supplying the shoulder and arm share common pathways to the brain. When an internal organ experiences distress, the brain may misinterpret these signals as coming from the shoulder.
Heart conditions are a common cause of referred pain to the left shoulder and arm. During a heart attack or angina (chest pain from reduced blood flow), the heart muscle experiences a lack of oxygen. Sensory nerves from the heart travel along pathways that innervate the left shoulder and arm, causing pain to radiate. This pain is often described as crushing or squeezing, and may be accompanied by chest discomfort, shortness of breath, sweating, or dizziness.
Irritation of the diaphragm, a large muscle separating the chest and abdominal cavities, can lead to referred shoulder pain. The phrenic nerve, which supplies the diaphragm, sends branches to the shoulder region. Conditions affecting organs near the diaphragm, such as a ruptured spleen, gallstones, or liver problems, can irritate it and cause pain in the left shoulder. A ruptured spleen, for instance, can cause sharp pain in the left shoulder, known as Kehr’s sign.
Lung conditions, such as pneumonia or pleurisy (inflammation of the lining of the lungs), can sometimes cause pain that refers to the shoulder. When the pleura, the membranes lining the lungs, become inflamed, the irritation can be perceived in the shoulder due to shared nerve pathways. This pain often worsens with deep breathing or coughing. Aortic dissection, a rare condition where the inner layer of the aorta tears, can cause sudden, severe pain that may radiate to the left shoulder, back, or chest.
Nerve-Related and Other Less Common Causes
Left shoulder pain can arise from issues involving nerves or systemic conditions. Nerve impingement, where a nerve is compressed or irritated, can cause pain that radiates into the shoulder. Cervical radiculopathy, originating from a pinched nerve in the neck, can send shooting pain, numbness, or tingling down the arm and into the shoulder. This compression results from a herniated disc or degenerative changes in the cervical spine.
Thoracic outlet syndrome is another condition where nerves or blood vessels between the collarbone and the first rib are compressed. This compression can lead to pain, numbness, tingling, and weakness in the shoulder, arm, and hand. Symptoms worsen with overhead activities or prolonged arm positions.
Systemic inflammatory conditions, which affect the entire body, can manifest as shoulder pain. Polymyalgia Rheumatica, an inflammatory disorder causing muscle pain and stiffness, commonly affects the shoulders and hips. The pain is worse in the morning and can limit movement. Fibromyalgia, a chronic condition characterized by widespread musculoskeletal pain, fatigue, and tenderness, can cause persistent pain in the left shoulder region or elsewhere.
Infections within the shoulder joint or surrounding tissues, or tumors, can cause localized pain. These causes are rare but can lead to persistent or worsening pain that does not respond to typical treatments.
When to Seek Medical Attention
Recognizing when left shoulder pain warrants medical attention is important for timely and appropriate care. Sudden, severe left shoulder pain, especially if it occurs with accompanying symptoms like chest pain, shortness of breath, profuse sweating, or dizziness, requires immediate emergency medical evaluation. These symptoms can indicate a cardiac event, and prompt assessment is important.
Pain that develops after an injury or trauma, such as a fall or a direct blow to the shoulder, necessitates medical attention. This is especially true if there is an inability to move the arm or shoulder, or if a visible deformity around the joint is present. These signs may indicate a fracture, dislocation, or soft tissue damage.
Any numbness, tingling, or weakness experienced in the arm or hand alongside shoulder pain should be evaluated by a healthcare professional. These symptoms can suggest nerve involvement or compression, which may require intervention. Pain that does not improve with rest or self-care measures, or pain that progressively worsens over time, warrants a medical consultation. This persistence could indicate an underlying condition requiring diagnosis and management. If left shoulder pain is accompanied by systemic symptoms such as fever, chills, or weight loss, medical attention is advisable to rule out less common causes like infection or systemic illness.