Occult pain on the left side of the stomach may be related to physiological factors such as improper diet and mental stress, as well as pathological factors such as cardiovascular system diseases and digestive system diseases. 1. Physiological factors: if overeating or eating spicy and stimulating, cold and greasy food, it will stimulate the gastric mucosa, and the patient may have hidden pain in the stomach. In addition, if there is emotional excitement, excessive pressure and other mental factors can also lead to vague pain in the stomach. 2. Pathological factors (1) Cardiovascular diseases: Since the heart is located near the stomach, if the patient has angina pectoris, myocardial infarction, coronary artery disease and other cardiovascular diseases, the left side of the stomach may also have hidden pain. (2) Digestive system diseases: gastric ulcer, chronic gastritis, pancreatitis, reflux esophagitis, gastric cancer, pancreatic cancer and other diseases may have the symptom of hidden pain on the left side of the stomach. There are many other causes of the above symptoms, if the symptoms persist or worsen, it is recommended to consult a doctor in time and make a clear diagnosis under the guidance of a professional physician to avoid delaying the condition.