The most common cause of hidden pain in the arm is local soft tissue strain. The soft tissues of the arm include muscles, fascia, tendons, ligaments and so on, all of which belong to the soft tissue category. The characteristic symptom of soft tissue strain in the arm is that the pain will increase when moving the arm, and the pain will be relieved after resting, sleeping and reducing the arm activity. The pain can be relieved after resting, sleeping, and reducing arm activities. The pain is especially noticeable when doing some special movements of the arm, such as holding a water bottle, wringing a towel, holding a child, etc. The strain is the cumulative injury or even inflammation caused by local strain, but the vague pain symptoms prove that the degree of injury is relatively mild.2. Some patients with cervical spine diseases, such as cervical spondylosis, cervical disc herniation, etc., if there is a slight compression of the nerves in the neck, it will cause soreness and discomfort in the arm and shoulder, but generally does not affect the activities of the arm.