Difficulty in breathing with chest tightness lying down after appendicitis surgery may be due to cardiac insufficiency, pericardial effusion, and other disorders that are usually unrelated to appendicitis surgery. 1. Cardiac insufficiency: it refers to the decrease of cardiac output caused by various reasons, which is mainly seen in various cardiomyopathies. There are no obvious symptoms in the early stage of cardiac insufficiency, and the main symptom in the later stage is rapid heartbeat, often accompanied by panic, shortness of breath, chest tightness and weakness. The main treatment includes improving the lifestyle, such as light diet, quit smoking and drinking, etc., and medication, such as digoxin and hydrochlorothiazide. 2. Pericardial effusion: mainly seen in exudative pericarditis, mainly female, the main symptoms are shortness of breath and chest pain, odd pulse. It can be treated with hormones and anti-inflammatory drugs, such as prednisone and cefozoxime. Pericardiocentesis etc. can also be performed. Lying down with chest tightness and dyspnea should be treated by a doctor to determine the primary disease.