The left side of the belly button sometimes hidden pain and sometimes no pain, may be intestinal dysfunction, intestinal tumors or long-term constipation caused by. 1. Intestinal dysfunction: the peristalsis of intestines will have certain rhythmicity, if the diet is not regular, and often in the state of mental tension and over-fatigue, it will affect the normal peristalsis of intestines, and the left side of the navel will sometimes have hidden pain and sometimes no pain symptoms. 2. Intestinal tumor: when there is a tumor in the intestinal tract, due to the continuous growth of the tumor, it will destroy the normal intestinal mucosa around it and may damage the nerve tissues, which may cause hidden pain or no pain on the left side of the navel in the early stage of tumor formation. 3. Long-term constipation: constipation will lead to the accumulation of feces in the intestines, long-term constipation, the accumulation of feces can not be discharged in a timely manner, will have an irritating effect on the intestinal tract, not only will there be an abnormal number of stools, there will also be a performance of the left side of the navel sometimes hidden pain sometimes painless. The left side of the belly button sometimes hidden pain sometimes not pain may also be caused by other reasons, it is best to do timely abdominal ultrasound and other ancillary tests to clarify the specific causes, and follow the doctor’s instructions for treatment.