The cause of arm pain at night may be arm pressure, excessive fatigue, cervical spondylosis, osteoporosis and other reasons, you should consult a doctor in time to find out the cause. 1. Arm compression: when sleeping due to posture causes arm compression, blood circulation is not smooth, may cause arm area muscle spasm, nerve spasm or edema, which leads to arm soreness. 2. Excessive fatigue: the use of the upper limbs during the day to carry out intense physical labor, which may lead to arm muscle fatigue, sleep at night, lactic acid accumulation and muscle edema resulting in muscle pain. 3. Cervical spondylosis: patients with cervical spondylosis sleep in the wrong position or pillow height is not appropriate, which can easily lead to pressure on the cervical nerves, causing muscle and fascial spasm, resulting in arm pain and numbness symptoms. 4. Osteoporosis: In the early stage of osteoporosis, due to the destruction of the peripheral bones, there are often symptoms of soreness in the limbs and spine at night. Frozen shoulder and other diseases may also lead to arm pain at night, when the symptoms of arm pain at night, you should consult a doctor in time to find out the cause, under the guidance of the doctor’s treatment.