Possible causes of chest discomfort include: respiratory system diseases, circulatory system diseases, mediastinal diseases, chest wall diseases, epigastric diseases and so on. 1. Respiratory system diseases: such as pneumonia, lung cancer, tuberculosis, pulmonary embolism, pleurisy, pleural tumor, pneumothorax, hemothorax, etc. can cause chest discomfort manifestations. 2. Circulatory system diseases: including angina pectoris, acute myocardial infarction, myocarditis, pericarditis, heart valve disease, congenital heart disease, aortic coarctation and so on can also appear chest discomfort symptoms. 3. Mediastinal diseases: including mediastinitis, mediastinal tumor, mediastinal emphysema and so on. 4. Diseases of chest wall: including subcutaneous cellulitis, intercostal neuritis, costochondritis, chest wall trauma, etc. 5. Upper abdominal diseases: certain upper abdominal diseases can also manifest as chest discomfort, such as chronic gastritis, esophagitis, gastroduodenal ulcer, liver abscess, hepatitis, hepatocellular carcinoma, subdiaphragmatic abscess, esophageal hiatal hernia and so on. Chest discomfort is a very common symptom, many diseases can be caused, there is no strong specificity, it is recommended that patients go to the hospital as soon as possible, combined with the condition of the consultation with a professional doctor, in order to clarify the cause and timely treatment.