Upward pain behind the left arm may be caused by cold or a posture, or may be caused by fasciitis, frozen shoulder, cervical spondylosis, rotator cuff injury and other disease factors, according to the different causes of targeted treatment. 1. Physiological factors: Cold or prolonged postures may cause local muscle spasms, which may lead to pain, which can be relieved through more rest and improved postures and other adjustments. 2. Fasciitis: avoid excessive activities, massage, hot compresses, infrared radiation and other physical therapy, such as pain is obvious, you can take oral ibuprofen extended-release capsules, celecoxib non-steroidal painkillers. 3. Frozen shoulder: to avoid cold, pay more attention to keep warm, you can pull the bar, drawing circles and other ways to exercise, to prevent adhesion of the joints, the pain is obvious can be closed injection and oral non-steroidal painkillers such as celecoxib and other treatments. 4. Cervical spondylosis: physical therapy and cervical traction can be taken to reduce the pressure of the intervertebral discs on the nerves, with non-steroidal painkillers such as Loxoprofen sodium, etc., conservative treatment is ineffective can be given to surgery. 5. Rotator cuff injury: Mild rotator cuff injury is mainly based on rest and braking, with local physical therapy to reduce edema, relieve pain and promote repair. Severe rotator cuff injury needs arthroscopic ligament and synovial membrane repair. The left arm back upward pain, through the rest of the hot compress can not be improved, you should promptly consult the doctor, and actively cooperate with the doctor treatment, to avoid delaying the condition.