The common causes of right shoulder pain are as follows: first, right shoulder periarthritis, which usually occurs in middle-aged people around 50 years of age, and is characterized by mild pain in the right shoulder at the beginning of the disease process and no limitation of shoulder joint range of motion. Thirdly, subacromial impingement syndrome, where the abnormal development of the subacromial bursa can cause shoulder pain due to impingement with the greater tuberosity of the humerus during shoulder lifting movements.