Pain at the back of the shoulder may be caused by myofasciitis, rotator cuff injury, frozen shoulder and cholecystitis. 1. Myofasciitis: the cause of myofasciitis is not clear, and it is considered to be related to prolonged or repetitive activities. Patients will have localized muscle pain, muscle tension, limited movement and other manifestations. 2. Rotator cuff injury: rotator cuff injury may be caused by indirect violence, degenerative disease, chronic strain and other reasons. Patients will have shoulder pain, shoulder joint swelling and activity limitation. 3. Frozen shoulder: the cause of frozen shoulder is not yet clear, and it is considered to be related to degenerative soft tissue lesions of the shoulder, long-term over-activity, trauma to the upper limb and other factors. Patients will have limited activities, pain around the shoulder joint and other manifestations. 4. Other: patients with cholecystitis, gallstones, myocardial infarction, angina pectoris, cervical spondylosis, muscle strain, trauma, shoulder bursitis and other diseases will also appear behind the shoulder pain. It is recommended that patients with pain behind the shoulder should go to the hospital in time, and the doctor will choose the appropriate treatment after clarifying the cause of the disease.