Pain in the chest after walking fast may be caused by braking, mainly due to spasm of the diaphragm, resulting in pain in the chest. After prolonged walking and strenuous walking, the skeletal muscles and the muscles of the limbs will consume much of the body’s nutrients and blood, which will cause the muscles inside the abdominal cavity, including the respiratory muscles, to suffer from transient ischemia and hypoxia and spasms, thus manifesting pain. One should immediately rest, try abdominal breathing to reduce the pain, or massage the chest area with the hands, or gently pat the chest area to relieve the pain. It is also possible that the patient has a stomach disorder, such as chronic gastritis or gastric ulcer, which may induce pain after walking for a long time, and the pain is very pronounced in the chest and upper abdomen. If necessary, gastroscopy can be performed to clarify the diagnosis. Gastroscopy can reveal chronic inflammation of the gastric mucosa, or ulcerative changes, which require medical treatment. Some patients have angina pectoris, so it is recommended to perform electrocardiogram and other tests to avoid delaying the diagnosis.