The inability to lift the arm to the back is related to frozen shoulder, rotator cuff tear and tendonitis. 1. Frozen shoulder: Frozen shoulder refers to the aseptic inflammatory reaction of the soft tissues around the shoulder joint, which is clinically manifested as pain in the shoulder and limitation of activities in all directions, so when suffering from frozen shoulder, it may result in inability to lift the arm to the back of the body. 2. Rotator cuff tear: Mostly caused by trauma or repeated shoulder joint movement, the shoulder muscles are torn, which can be manifested as pain in the neck and shoulder area, obvious weakness and limitation of shoulder lifting activities, and then the arm can not be lifted to the back. 3. Tendonitis: When tendonitis occurs in the long head of the biceps muscle located in the shoulder, due to the inflammatory stimulation of the arm lifting backward, it will cause obvious pain in the shoulder, which will result in the inability to lift backward, commonly seen in the people who have long time excessive physical labor or throwing sports. The arm can not be lifted backward may also be related to other reasons, it is recommended to consult a doctor in a timely manner, to carry out relevant examinations to clarify the cause of the disease, and standardized treatment under the guidance of the doctor.