One year after bowel cancer surgery, left side chest pain may be caused by pneumothorax, bacterial pneumonia, lung metastatic cancer, etc. General treatment, drug or surgical treatment, radiotherapy or chemotherapy should be carried out to treat the cause. 1. For pneumothorax, bed rest can be provided, oxygen therapy can be provided if necessary, and patients with severe pneumothorax can be pumped or drained; for those who are ineffective in conservative treatment, open thoracotomy, small-opening thoracotomy via axillary front line can be performed. 2. For bacterial pneumonia, patients can take antibiotics such as amoxicillin and expectorants such as ambroxol as prescribed by doctor. 3. For metastatic lung cancer, for those who can tolerate surgery, have no extra-thoracic metastasis and can control the primary tumor, appropriate surgical treatment can be chosen according to the specific situation, supplemented by radiotherapy and chemotherapy. It is suggested that those who have left-sided chest pain one year after surgery for intestinal cancer should go to regular hospitals in time, clarify the cause of the disease and standardize the treatment under the guidance of doctors.