Five years after lung cancer surgery, the left chest incision is always swollen and painful, which may be related to infection, pleural effusion, pneumothorax, etc. Different causes of different medication programs, such as infection can be used with cefadroxil capsule, pleural effusion can be used with mitomycin for injection, pneumothorax can be used with ceftriaxone sodium for injection, etc. It is recommended to use medication under the guidance of doctor, avoid self-medication to avoid delaying the condition. 1. Infection: such reasons as irregular use of antibiotics, diabetes, dead space left in the incision suture, low immunity may lead to infection of the left chest incision after five years of lung cancer surgery, and there is always swelling and pain. This kind of patients can use cephalosporins, penicillin and other medicines as prescribed by doctors for anti-infection treatment. 2. Pleural effusion: it refers to the lesion manifestation caused by liquid in chest cavity. When the patient has fluid in the chest cavity, the lungs will expand because of breathing, which can cause the friction between the dirty pleura and the wall pleura, and then the symptom of chest pain. The left chest incision is always swollen pain can be considered as the patient’s chest cavity with fluid, such patients can follow the doctor’s instructions to use mitomycin, bleomycin and other drugs treatment. 3. Pneumothorax: refers to the state of gas accumulation caused by gas entering the pleural cavity. Due to the increased pressure in the chest cavity of patients with pneumothorax, the pleura causes certain pulling, which can cause chest swelling and pain. The left chest incision is always swollen and painful may be the manifestation of pneumothorax. This kind of patients are usually treated with exhaust. It is recommended that the patient consult the doctor in a timely manner, after a clear diagnosis under the guidance of the doctor to use medication.