There are the following reasons for stomach pain when eating: 1. Stomach pain caused by gastric ulcer is generally manifested as dull pain, distension, burning pain and so on. The pain is strong within an hour after eating, and will be relieved two hours after the meal. 2, when eating, wolf swallowing, on the one hand, will bring a lot of burden to the stomach and intestines, on the other hand, there will be a lot of air with the food into the body. The air is mixed in the food, together with the stomach peristalsis will lead to stomach pain. 3, gastritis causes hidden pain in the stomach and not regular, the pain is also relatively wide, generally after the meal pain is strong, fasting when the pain will be relieved. The pain will be more intense especially if you eat stimulating food, and there will be nausea, vomiting and other symptoms.4. Eating cold food will strongly stimulate the stomach and intestines, which can easily lead to stomach cramps and lead to stomach pain, and eating too much will also lead to diarrhea.