Pain on the outer side of the big arm may be caused by tennis elbow, frozen shoulder, cervical spondylosis, and so on. 1. Tennis elbow: this disease is mainly due to long-term, repeated forceful activities of the forearm, resulting in the epicondyle of the humerus chronic injury inflammation, and its typical symptoms are the lateral elbow pain, burning and so on. 2. Frozen shoulder: the etiology of this disease is not yet completely clear, usually thought to be caused by the joint capsule fibrosis and synovitis, often triggered by frequent lifting and pulling of heavy objects, long-term lack of exercise and other triggers, resulting in shoulder pain, impaired mobility and other symptoms, because the shoulder nerve will be driven to the arm, so some patients may be present in the performance of the outer side of the big arm pain. 3. Cervical spondylosis: the occurrence of this disease is related to chronic strain injury, cervical degenerative changes, cervical spine developmental spinal stenosis and other reasons, can be triggered by sudden impact, cold wind stimulation and other factors, resulting in the patient’s neck pain, stiffness, and some patients may experience upper extremity pain or numbness. There are more causes of pain on the outside of the big arm, and it is necessary to go to the hospital for consultation to clarify the cause of the disease.