Left spine pain may be related to trauma, disc herniation, myofibrositis and other causes. 1. Trauma: When the back is hit or collided by external force, it can lead to bone or soft tissue injury in the spine, which produces pain, and patients usually have a clear history of trauma. 2. Herniated disc: when the lumbar or thoracic intervertebral disc undergoes degenerative changes and irritates the nerves or nerve roots, pain and numbness in the innervated area can occur, and thoracic and lumbar spine CT and MRI can be used to make a clear diagnosis. 3. Myofibrositis: the back muscles are rich, under the influence of cold, tiredness, excessive exercise and other factors, aseptic inflammation of muscles can occur, resulting in pain. Generally the pain is more limited and can be aggravated by activities. The left side of the back pain can also be seen in other causes, the patient should go to the hospital in a timely manner, under the diagnosis and guidance of a professional doctor for treatment.