Pain in the middle of the chest when exerting oneself may be related to rib fracture, costochondritis, chest soft tissue strain, respiratory system disease, cardiovascular disease and so on. 1. Rib fracture: most of them have history of trauma, because the external violence acts on the ribs, resulting in incomplete fracture of the ribs, with mild displacement, before complete healing, there will be pain in the middle of the chest when exerting oneself. 2. Costochondritis: mostly caused by non-infectious factors, chest pain and pressure pain, caused by infectious factors may also appear local skin redness, swelling, heat and pain. The pain may radiate to the back of shoulder, armpit, cervical and thoracic region, and may be aggravated by deep breathing, activity or exertion. 3. Chest soft tissue strain: chest soft tissue strain is usually caused by bad exercise habits, soft tissue strain will have local aseptic inflammation, a force will cause irritation and pain. 3. Respiratory diseases: such as pulmonary alveoli, when strenuous activities or sudden changes in body position, may cause pulmonary alveoli rupture resulting in abnormal chest pain, pain is more pronounced when exertion. 4. Cardiovascular system diseases: especially patients with coronary heart disease, because of the activity of exertion caused by increased myocardial oxygen consumption, myocardial ischemia, hypoxia, there will be after exertion chest pain and other symptoms, often accompanied by tightness in the chest, shortness of breath, should immediately stop the activity of exertion, timely rest, calming emotions. It is recommended to go to the hospital to check the symptoms of pain in the middle of the chest after exertion, and find out the cause of the pain under the guidance of the doctor.