Sudden pain in the arm is considered to be caused by physiological factors such as weight bearing on the arm, strenuous exercise, etc. It may also be caused by other reasons such as trauma, epicondylitis of the humerus, and cervical spondylosis. 1. Physiological factors: if the arm in a short period of time to lift heavy objects or by heavy pressure, or arm strenuous exercise may lead to arm lactic acid buildup, there may be a sudden arm pain performance. 2. Trauma: the arm is hit by external force or localized scratches by sharp objects, which may cause arm pain, bleeding and other manifestations. As a result, the patient will have the symptom of sudden pain in the arm. 3. Epicondylitis of humerus: Epicondylitis of humerus may be the injury of tendon and epicondyle of humerus caused by repeated or long-term contraction of extensor muscles of the anterior wall, and the patients will have the manifestations of pain, burning and joint popping on the lateral side of the elbow. So the patient presents with lateral epicondylitis of the humerus, there will be a sudden pain in the arm manifestation. 4. Other: patients with sudden pain in the hand is also considered to be nerve root cervical spondylosis, frozen shoulder, osteoarthritis, muscle strain, peripheral neuropathy, arm sprain and other diseases. If it is physiological factors caused by sudden pain in the arm can not be treated, if it is a disease caused by sudden pain in the arm, you need to consult a doctor in a timely manner, you need to follow the doctor’s instructions to choose the appropriate measures for treatment.