There are many reasons for pain in the middle of the chest, such as trauma, heart disease, respiratory disease, digestive system disease and other diseases. 1. Trauma: when the sternum or chest muscles and soft tissues are traumatized, bone fracture, fracture, soft tissue contusion can be manifested as pain in the middle of the chest. 2. Heart disease: when suffering from angina pectoris or myocardial infarction, it can be manifested as pain behind the sternum, mostly occurring after exertion, and the pain is generally more intense, and myocardial infarction patients have persistent pain that can not be relieved, which is often accompanied by dyspnea, sweating, and even a sense of imminent death. 3. Respiratory diseases: when suffering from pleurisy, massive pneumonia, pulmonary embolism, advanced lung cancer, it can also be manifested as pain in the middle of chest. 4. Digestive system diseases: when suffering from gastroesophageal reflux disease or other esophageal diseases, such as esophageal tumor compressing the surrounding organs and tissues, the above manifestations can also appear. 5. Other diseases: when suffering from sternal tumor or leukemia infiltrating the sternum, pain in the middle of the chest will also appear. There are many reasons causing pain in the middle of the chest, when there is pain behind the sternum or in the middle of the sternum, timely diagnosis and treatment should be made to avoid delaying the condition.