Left back pain in the middle of the back generally have the following reasons: 1, myofasciitis, when there is myofasciitis will appear in the middle of the left back pain, accompanied by numbness of the left side of the upper limbs, weakness, especially in the night time when the pain in the sleep of the very obvious. 2, cardiac disease, when there is a heart attack or angina pectoris will be the left back of the radiating pain, then to carry out electrocardiograms to further diagnosis, as well as the cardiac enzymes. 3, herpes zoster, herpes zoster can be early in the early stages of pain. 3, herpes zoster, herpes zoster early can appear in the middle of the left back pain. At this time, it is necessary to carry out dermatological consultation to observe whether there is blister formation in the skin, if there is blister formation, it can further confirm the diagnosis.4, is it a tumor of the rib itself that causes headache, when there is a metastatic tumor in the rib it will appear back pain.