Pain and discomfort in the middle of the chest can be caused by physiologic factors, such as overexertion or strenuous exercise. Excluding physiological factors may be caused by diseases, such as osteoarthritis, lung disease, reflux esophagitis and heart disease. 1. Physiological factors: After overexertion or strenuous exercise, the muscles of the body are in a state of tension, which can easily cause lactic acid accumulation, further leading to pain and discomfort. 2. Pathologic factors: (1) Bone and joint inflammation: costochondritis, sternoclavicular arthritis, etc., will cause related symptoms, and local soft tissue and nerve stimulation. (2) Lung diseases: Pneumonia, pleurisy and lung cancer may cause irritation to the pleura and affect the neighboring nerves, which may lead to pain and discomfort. (3) Reflux esophagitis: Gastroesophageal reflux burns the esophageal mucosa, which may cause retrosternal pain. (4) Heart disease: the presence of coronary artery stenosis, which further leads to insufficient blood supply, can also cause pain and discomfort in the middle of the chest. Apparent post-sternal pain has not been relieved, there may be other reasons, you need to consult a doctor in time to observe, through clinical examination to determine the cause of the disease, standardized treatment under the guidance of the clinician, to avoid delays in the condition.