There are three main reasons for pain in the shoulder-arm joint: First, the soft tissues of the shoulder-arm joint, such as muscles, tendons, ligaments, and fascia, may become strained or damaged, resulting in localized bruising and swelling, as well as inflammatory edema, which may stimulate the peripheral nerves and cause pain, especially if the pain is more pronounced with continued activity. Second, there may be adhesions in the shoulder joint and arm joint, for example, if the shoulder joint is not moved for a long time, if it is fixed in a cast or brace after a traumatic injury, or if there is a lack of activity in the shoulder joint after other surgeries, this may lead to adhesions, and when the shoulder and arm joint are moved, the adhesions will be pulled and there will be obvious pain. Thirdly, if the shoulder joint and arm joint have a sterile inflammatory lesion, such as a previous trauma, or frequent cold or strain, resulting in the formation of a chronic local lesion, if there is cold and strain again, it may lead to more and more inflammation and obvious pain.