The left arm pain may be caused by viral colds or epicondylitis of the humerus. 1. Viral colds: If there is a viral infection in the body, it may trigger a cold, and as the disease develops, it may cause the patient to have a sore throat, nasal congestion, or coughing, coughing up phlegm, accompanied by limb pain, and some patients may have left arm pain when they have a cold. 2. Epicondylitis of the humerus: the patient’s own immunity during the cold, if accompanied by epicondylitis of the humerus, may also lead to the patient to appear a cold on the left arm pain, especially on the outside of the elbow joint pain is more obvious. Arm pain can also be caused by other reasons, it is recommended to go to the regular hospital in time for examination, to clarify the cause of further treatment.