Inexplicable soreness in the left arm and numbness in the fingers are, first of all, considered to be caused by physiological factors, such as prolonged holding of the left arm in one position or continuous exertion, which affects the local blood supply. It is recommended to eliminate the triggering factors in time to relieve the above discomfort. Second, it is considered to be caused by pathological factors, such as cervical spine disease, shoulder periarthritis, angina pectoris, myocardial infarction and so on. It is recommended to find the cause in time and implement treatment as soon as possible. I. Physiological factors: Due to long time keeping a posture or continuous exertion of the left arm, the left hand is continuously compressed, resulting in the nerves and muscles of the left arm having insufficient blood supply due to impaired blood circulation and showing the above discomfort symptoms. It is recommended that local hot compresses, massage or acupuncture treatment be implemented in a timely manner to help improve the symptoms of discomfort. If the symptoms are heavy, you can take oral vitamins, methylcobalamin and other neurotrophic drugs to speed up the relief of symptoms. Pathological factors: 1. Cervical spine diseases: cervical spine hyperplasia or cervical disc herniation are common. As cervical spine diseases compress the nerves that govern the sensory and motor functions of the left upper limb, resulting in inexplicable soreness of the left arm and numbness of the fingers. It is recommended that cervical spine traction treatment or local hot compresses, massage, acupuncture, etc. be given in a timely manner to help improve the above discomfort. 2. Shoulder periarthritis: Degenerative changes in the soft tissues of the shoulder, or chronic strain or trauma to the shoulder, cause inexplicable soreness in the left arm and numbness in the fingers. It is recommended to rest in bed immediately and keep the shoulder joint in a resting position, while assisting local physiotherapy to relieve the symptoms, or take oral anti-inflammatory and analgesic drugs such as ibuprofen as prescribed by the doctor. 3, angina pectoris, myocardial infarction: due to previous history of arteriosclerosis or hypertension, when emotional excitement, strenuous exercise and other factors interfere, it is easy to have insufficient blood supply to the heart muscle and increase oxygen consumption and induce angina pectoris, which can develop into Myocardial infarction. In addition to the crushing pain in the anterior chest area, it is accompanied by inexplicable soreness in the left arm and numbness in the fingers. It is recommended to rest immediately while taking nitroglycerin under the tongue to relieve the pain, and to seek medical attention immediately to avoid delaying the disease; 4. Other: such as rheumatism, myofasciitis, spinal cord tumor or head tumor, etc., can also appear the symptoms of inexplicable soreness in the left arm and numbness in the fingers, it is recommended to actively seek medical treatment and improve CT, MRI and other examinations. For example, rheumatism can be treated with infrared irradiation, electrotherapy, and heat therapy to numb nerves and relieve joint pain, combined with immunosuppressive drugs such as methotrexate and hydroxychloroquine if necessary. Patients with myofasciitis avoid exertion and strain, repeated exposure to cold, and do more acupuncture and massage physiotherapy to relieve discomfort. Patients with head tumor need to actively undergo surgery to remove the tumor and follow medical advice to choose chemotherapy and radiotherapy according to the disease condition. During the treatment period, it is recommended to maintain a light and easy-to-digest diet, and to exercise appropriately to help promote early recovery of the disease.