Cramp-like pain below the chest is more likely to be due to pleurisy from a variety of causes. When fluid accumulates inside the chest cavity due to chest infection, tumor, tuberculosis, inflammation, etc., the pleural fluid will gradually disappear as the inflammatory factors are eliminated, but the fibrin in the pleural fluid may be deposited and converted to fibrin, which subsequently becomes mechanized and adherent, and will adhere the pleura together. This increases friction when breathing and causes cramp-like pain below the chest. In addition, abdominal lesions may also cause pleural effusion, resulting in cramping pain below the chest when breathing. Therefore, if there is no relief within a short period of time, it is important to go to a regular hospital in a timely manner.