If the left side of the stomach hurts even when lying on the side, you need to consider the possibility of left colon obstruction, colitis, abdominal abscess and so on. 1. If left colon obstruction is not relieved in time, there will be pain in the left side of the abdomen, abdominal distension, stopping of defecation, etc., which can not be relieved even when lying on the side. In a few cases there may be vomiting. The disease can be treated conservatively, such as water fasting, parenteral nutrition and enemas, and surgery is needed if necessary. 2. Colitis often appear abdominal pain, increased stool frequency, diarrhea, etc., the case requires timely drug treatment, often use antibiotics (such as amoxicillin, etc.), if necessary, also need to use probiotic drugs. Note that the two are generally not recommended to take the same, can be spaced out. The above drugs need to be under the guidance of a professional doctor. 3. Peritoneal abscesses often cause pain in the surrounding tissues, as well as persistent high fever, anorexia, night sweats, etc. The situation often requires surgical treatment with puncture and drainage, as well as strengthening rehydration, nutritional support and other auxiliary treatment. The left side of the stomach pain side lying also pain may also be inflammatory bowel disease, acute gastroenteritis and other conditions, if the above situation, please consult a doctor in time for reasonable and standardized diagnosis and treatment.