The diseases that should be alerted to arm pain are cervical spondylosis, rotator cuff injury, herpes zoster, tumor, muscle strain. 1. Cervical spondylosis: cervical spine hyperplasia compressing the nerve can appear arm pain, radiating to the fingers, some will have numbness, through the cervical spine MRI film can be clearly diagnosed. 2. Rotator cuff injury: degeneration of shoulder joint or injury of shoulder ligament can cause shoulder joint pain, and involve arm pain. Shoulder joint activity is limited, taking shoulder MRI films can make a clear diagnosis. 3. Herpes zoster: there are mostly localized rash blisters, and invasion of nerves can cause arm pain. 4. Tumor: bone tumor causing bone destruction can cause arm pain, and CT can find that the tumor invades bones and soft tissues. 5. Muscle strain: if the arm is often in a fixed position, it can cause muscle strain, and if you often do tired work, it can cause arm pain. If the arm pain does not get better after resting, you need to go to the hospital for examination.