Shoulder pain when raising the right arm may be due to several reasons: i. The most common cause is frozen shoulder, which occurs in patients who are relatively old, usually 50 years old or younger, so it is also known as the 50th shoulder. Second, biceps longus tendonitis in the right shoulder. Once this inflammation sets in, it causes shoulder pain when the right arm is lifted. Third, other less common causes may be rotator cuff injury of the right shoulder joint, fracture of the right shoulder joint and dislocation of the right shoulder joint, or even bone tumor and soft tissue tumor of the right shoulder joint.