Hidden pain in chest during postoperative chemotherapy for lung adenocarcinoma is generally a normal phenomenon, but it is also necessary to be alert to diseases such as pleural adhesion, hemopneumothorax and other diseases such as pleural effusion. 1. Normal phenomenon: patients with lung adenocarcinoma have hidden pain in chest during chemotherapy, the chemotherapy drugs may cause some damage to the normal cells around, resulting in hidden pain in chest, which is a normal phenomenon. 2. Pleural adhesion: pleural adhesion is mainly caused by pneumonia, lung cancer and other diseases, and patients will have chest pain, chest tightness, dyspnea and other symptoms. If lung adenocarcinoma is complicated by pleural adhesion, it will lead to hidden pain in the chest, which is not normal. 3. Hemopneumothorax: Hemopneumothorax is caused by malignant tumor in chest, and the main symptoms of patients are chest pain, dyspnea, rapid heartbeat and so on. If lung adenocarcinoma is complicated with hemopneumothorax, it will also lead to hidden chest pain, which is abnormal. 4. Others: if patients with lung adenocarcinoma have complications of other diseases such as pleural effusion, pneumothorax, etc., they will also have hidden chest pain, which is also abnormal. When patients with lung adenocarcinoma have symptoms of hidden pain in chest during chemotherapy, it may be normal, or it may be caused by concurrent diseases. Patients should consult doctor in time and follow the doctor’s instruction.