Shoulder pain is very common when practicing chest, the mechanism of this situation is mainly the following: 1, may be in the practice of chest at the same time, causing damage to the tendons of the shoulder. Because the pectoralis major muscle itself is stopped at the small node below the shoulder, that is, on the humerus. While practicing chest, the tendons here may produce fatigue damage, which may lead to pain. In addition, during the process of chest force, the shoulders must be forceful with it. If the tendons inside the shoulder joint, such as the rotator cuff, are damaged in this area, shoulder pain will also occur. 2. This condition may be caused by overworked muscles in the shoulder. In the process of exercising the chest, the muscles of the shoulder also need to be coordinated with the force. Only then can the entire upper limb make a series of coordinated movements. Therefore, it is possible that the muscles of the shoulder may become fatigued and cause pain when the chest is being exercised at the same time. 3. If the patient has congenital genetic factors that cause the position of the shoulder peak to be too narrow, or if there is excessive osteophytes, it may cause the tendon and bone to hit here, and then produce pain after chest training.