Hidden pain in the lower left side of the navel may be caused by acute gastroenteritis, ureteral stones or ulcerative colitis. 1. Acute gastroenteritis: Acute gastroenteritis can be induced by eating unclean food, and the patient will also show symptoms such as lower left abdominal pain, nausea and vomiting. 2. Ureteral stones: Ureteral stones cause pain in the left lower abdomen, which is supposed to be a case of colic during the movement of the stone. 3. Ulcerative colitis: the left side of the navel is a part of the descending colon, once ulcerative colitis is present in the descending colon, the patient’s left side of the navel will be accompanied by pain. These are only some of the common causes. If the symptoms persist, the patient should go to the hospital in time, under the diagnosis of the doctor to determine the cause of the disease, according to different situations to take the appropriate treatment for treatment.