Pain under the chest has the following conditions: a. Inflammation of the lower lung, inflammation of the lower lung can appear as pain under the chest, usually caused by pneumonia involving the pleura, this chest pain is related to breathing, usually the pain increases when inhaling deeply, coughing, turning the position, and chest pain can be reduced or disappeared by holding the breath. At the same time, the patient may have fever, cough, sputum, dyspnea and other symptoms. It is recommended to do chest X-ray or lung CT for clear diagnosis. Second, the pain under the left chest also requires attention to heart disease, including angina pectoris and acute myocardial infarction in coronary heart disease. Angina pectoris generally has a short duration of pain that lasts for several minutes, and the pain is mild and can usually be relieved after resting or containing nitroglycerin. Acute myocardial infarction, the pain is more intense and lasts longer, generally more than 15 minutes, or even up to several hours, it is recommended to do electrocardiogram and myocardial enzyme spectrum examination to make a clear diagnosis. Third, the lower left chest also needs to pay attention to stomach diseases, such as gastritis, gastric ulcer when the patient may have epigastric pain, accompanied by nausea, vomiting, acid reflux, belching and other symptoms. Fourth, pain under the right chest should pay attention to diseases of the hepatobiliary system, such as cholecystitis, gallbladder stones, liver cancer, etc. It is recommended to do hepatobiliary and splenic ultrasound for clear diagnosis.