There are three main principles of stomach pain: 1. Mucosal damage. After mucosal injury, the nerves within the mucosa are also damaged, thus producing the symptoms of stomach pain. 2. gastric distension, which is mainly caused by poor function and distension due to excessive eating, is caused by high tension. 3. spasmodic pain, which is mainly caused by spasm of stomach muscles due to various stimuli, and produces pain. The above three pain principles can be caused by diet or by diseases, such as eating cold, spicy, greasy or drinking alcohol, strong tea, strong coffee, etc.; and diseases such as inflammation, erosion, ulcer, malignant tumor of the stomach can be caused.