There are many causes of stomach pain, which can be divided into the following three categories: 1. External stimulation, such as drinking alcohol, smoking, drinking strong tea, eating cold, spicy and greasy food, etc., can cause the stimulation of gastric mucosa and produce symptoms of stomach pain. 2. Benign diseases of the stomach, such as gastric inflammation, erosion and ulcer, can also cause symptoms of stomach pain. 3. malignant tumors can also cause stomach pain, which may be accompanied by symptoms such as wasting and weakness. Besides, even if the patient has some gastric diseases or even gastric cancer, there may be no clinical symptoms in the stomach and need relevant examination before being detected.