The pain of lifting the right arm upward and outward may be caused by muscle strain, or it may be caused by frozen shoulder, subacromial impingement syndrome, rotator cuff injury and so on. 1. Muscle strain: muscle strain caused by improper exertion or strenuous activities of the shoulder joint, which may result in the symptom of pain of lifting the upper arm of the right arm upward and outward. 2. Frozen shoulder: self-limited aseptic inflammation of the soft tissues around the shoulder joint for unknown reasons, with the main clinical symptoms of shoulder joint pain and activity limitation, and the phenomenon of pain in lifting the upper arm of the right arm upward and outward can occur. 3. Subacromial impingement syndrome: Inflammation of subacromial space due to repeated impingement and abrasion of acromion and humeral tuberosity, which can be manifested as pain in shoulder and deltoid muscle innervating area when the arm is lifted upward. 4. Rotator cuff injury: aseptic inflammation or rupture of rotator cuff tendon caused by various reasons, leading to pain in the right arm when the upper arm is lifted upward and extended outward. There are many other causes of this symptom, if the above symptoms occur, it is recommended to enter the hospital to find out the cause of the disease and actively cooperate with the doctor’s treatment in order to relieve the symptoms.