The shoulder joint is a relatively complex joint in the human body, with muscles, tendons, ligaments, joint capsule, joints, cartilage and other structures. The shoulder joint is not limited to bones, but there are many structures in the shoulder joint that can make a sound. The contraction of the muscles slides in the soft tissue spaces around the joint. Once the contraction is too fast, the muscles will rub against the surrounding soft tissues and even bony structures, resulting in a localized rattling sound. Most of these sounds are not very crisp and loud. 2. Looseness of the joint capsule of the shoulder joint is also the cause of a ringing sound in the shoulder joint. If there has been a trauma to the shoulder joint, or even a fracture or dislocation of the shoulder joint, there may be damage to the joint capsule and the surrounding soft tissue. The injury will cause the joint capsule and the soft tissue to relax, and the shoulder joint will be in an unstable state. Once the shoulder joint moves to a certain angle or does certain movements, the shoulder joint will collide and ring.