What Causes Soreness and Pain in the Left Shoulder?

Left shoulder soreness and pain are relatively complex, and we can consider the following five possibilities:

1. Cervical–shoulder pain caused by trauma: Immediate left shoulder joint pain, swelling, and functional impairment may occur following trauma; fractures may also be present. Recurrent left shoulder joint pain may be attributable to overuse of shoulder muscles, excessive loading, or exposure to cold and damp weather.

2. Pain caused by infectious shoulder joint disorders: In addition to common shoulder joint pain, such infections may present with systemic signs including high fever and chills, along with local inflammatory manifestations. Movement of the affected shoulder joint elicits marked pain, regardless of the direction of motion.

3. Pain secondary to other systemic diseases: For example, rheumatoid arthritis and systemic lupus erythematosus are autoimmune disorders. Left shoulder joint pain associated with these conditions is often accompanied by involvement of other organ systems; patients should therefore seek evaluation at a hospital’s rheumatology or immunology department.

4. Metabolic disorders may also cause left shoulder joint pain—for instance, osteoporotic arthropathy or osteoarthritis secondary to thyroid or parathyroid disease.

5. Patients presenting with left shoulder joint pain must remain highly vigilant for early signs of myocardial infarction or angina pectoris, as referred pain from cardiac ischemia may manifest solely as left shoulder discomfort. Because left shoulder pain may be the initial symptom, misdiagnosis or delayed diagnosis—and consequently, delayed treatment—may occur.