The most common causes of small arm muscle pain are strenuous exercise, soft tissue injury, tennis elbow, cervical spondylosis, vasculitis, etc. If the symptoms persist, it is recommended to seek medical treatment in time. 1. Strenuous exercise: patients carry out arm activities, such as throwing a shot put, playing badminton, strenuous exercise will easily cause lactic acid accumulation, which in turn causes pain. 2. Soft tissue injury: the small arm muscles are hit and squeezed, causing muscle tears and injuries, etc., which will also cause pain in the small arm muscles. 3. Tennis elbow: repeated twisting of the arm or overstretching of the arm may cause inflammation and edema of the epicondyle of the humerus, which may also cause pain in the arm. 4. Cervical spondylosis: After the cervical disc compresses the nerve root, the pain will be radiated to the upper arm, which will cause pain. 5. Vasculitis: usually occurs in the lower extremities, is a chronic, occlusive inflammatory disease, may also produce symptoms in the arm, arm cold and pain. Causes of small arm muscle pain causes more, if rest does not relieve, it is recommended to go to the hospital in time to identify the cause of the disease, by the doctor targeted treatment.