Back pain may be a precursor of lung cancer, but it may also be caused by muscle strain or trauma. 1. Lung cancer: Some patients with early stage of peripheral lung cancer may have back pain due to pulling of mass, which may be accompanied by coughing, coughing up sputum, blood in sputum and so on. 2. Muscle strain: back pain may be caused by muscle strain. If the patient engages in physical labor for a long time, it will lead to injury of back muscles, forming a kind of sterile inflammation, and the pain will appear under the repeated stimulation of inflammatory factors. 3. Trauma: If the patient’s back has been hit or impacted, it will lead to back injury, and in serious cases, even fractures will occur, thus causing back pain. When the symptoms of back pain appear, it is necessary to consult a doctor in time for examination and treatment for the cause of the disease.