Left shoulder pain sometimes accompanied by back pain, there may be several causes: a. Heart disease, when there is angina pectoris or heart attack will appear left shoulder pain, at the same time can be accompanied by occasional pain in the back, this time to conduct electrocardiogram examination and related blood tests to further confirm the diagnosis and treatment. Myofasciitis, myofasciitis can occur in the left scapula medial pain, accompanied by back pain, can also radiate to the left upper limb, especially at night when sleeping arm pressure is very obvious pain. Third, tumors of the scapula or ribs can also cause pain in the left shoulder, accompanied by pain in the back, then CT, ECT or X-ray examination should be performed to further confirm the diagnosis and treatment.