There are two main possibilities for chest pain in the middle of the night: 1, cystic hyperplasia of the breast, which occurs in women of childbearing age between 30 and 50 years old, mainly related to endocrine hormone disorders caused by breast hyperplasia and incomplete replenishment, the clinical manifestation of breast pain with changes in the menstrual cycle, due to the vagus nerve excitation at night can cause hormonal changes in the body, thus inducing acute attacks of cystic hyperplasia of the breast phenomenon of chest pain. 2, reflux esophagitis, the onset of which is mostly related to the relaxation of the sphincter at the site of gastroesophageal union. At night, because the body is lying down for a long time, it can lead to a decrease in the pressure in the gastroesophagus, which leads to a large amount of gastric acid reflux into the esophagus and a burning pain behind the sternum, and can be accompanied by belching and acid reflux discomfort. When chest pain occurs in the middle of the night, you should go to a regular hospital in time to identify the cause of chest pain and actively cooperate with a specialist.