Sleeping up arm pain, may be improper sleeping posture, frozen shoulder, exertion, nerve pain and other causes. 1. Improper sleeping posture: improper sleeping posture, compression of the upper limb nerves, may lead to a sleep up arm pain. 2. Frozen shoulder: aseptic inflammation of the shoulder joint and surrounding soft tissues may also lead to the symptoms. 3. Exertion: Excessive exercise, overwork, and long-term posture may cause muscle ligament strains, which may also lead to the symptoms. 4. Nerve pain: such as peripheral neuritis, cervical spine disease compression of local nerves, or herpes zoster caused by nerve damage, can also cause the symptoms. Sleeping up arm pain, there may be other reasons, need to go to the hospital in time to check, clear cause.