Stomach pain when eating may be caused by eating too fast, or it may be caused by gastric ulcer, active gastritis, pancreatitis and so on. 1. Eating too fast: If you eat too fast during the meal, it is easy to increase the burden on the gastrointestinal tract, and at the same time, there may be more air into the body, which will cause the stomach and intestines to peristalsis, resulting in the phenomenon of stomach pain. 2. Gastric ulcer: gastric ulcer patients are prone to gastric pain at the time of proceeding, mainly due to food stimulation of gastric acid secretion, the gastric mucosa caused by a certain impact, thus manifested as gastric pain, usually presenting a dull pain, distension, burning pain and so on. 3. active gastritis: when gastritis is in the active stage, eating will also cause stimulation to the gastric mucous membrane which has inflammation, thus causing the symptoms of gastroparesis. 4. Pancreatitis: When pancreatitis is present, the patient may also experience stomach pain after eating, usually with epigastric pain, abdominal distension, nausea, vomiting, and decreased bowel movements. In addition to the above factors, there may also be other causes, it is recommended to consult a doctor for examination and clarification.