Soreness at the back of the left shoulder needs to be treated with reasonable medications according to the cause, such as non-steroidal anti-inflammatory drugs, nutritive nerve medications, blood-activating and blood-stasis-relieving Chinese patent medicines, and vasodilating medications. The more common causes are cervical spondylosis, frozen shoulder, strain and heart disease. 1. Cervical spondylosis: Cervical spondylosis can lead to pulling pain in the left shoulder, especially if the lesion site causes compression on the nerve root, which can cause soreness at the back of the left shoulder. Non-steroidal anti-inflammatory drugs such as ibuprofen can be given to treat the pain, and drugs such as vitamin B1, methylcobalamin and other nerve-nourishing drugs can be given to treat the pain due to nerve root compression. 2. Frozen shoulder: in addition to pain and limitation of shoulder joint, it can also lead to soreness behind the left shoulder, which can be treated with non-steroidal anti-inflammatory drugs such as diclofenac sodium. 3. Strain injury: it is mostly related to the left shoulder strenuous exercise, weight bearing and other factors, and can be treated with Chinese medicines that activate blood circulation and eliminate blood stasis, reduce swelling and relieve pain, such as blood circulation and pain relief capsule, shujin and blood circulation tablets and so on. 4. Heart disease: mainly seen in ischemic cardiomyopathy, such as angina pectoris, myocardial infarction, etc., in addition to the pain in the precordial area, some of them can also lead to the pain behind the left shoulder, and need to be given to increase the blood supply to the myocardium and reduce the burden on the heart of the vasodilator drugs, such as nitroglycerin, etc. There are also other causes of pain behind the left shoulder. There are other causes of pain behind the left shoulder, such as trauma, etc., such as persistent non-relief, it is recommended to timely visit the hospital, improve the examination to clarify the cause of the disease, follow the doctor’s instructions for targeted treatment, do not blindly use their own medication, so as not to delay the condition.