Your description is inadequate, but my judgment is that you have a ventral hernia. A hernia is the protrusion of abdominal contents, like intestines, through a hole in the fascia, which is the strong tissue that surrounds the intestines. The intestines protrude to come to lie under the skin, causing a bulge. Hernias are likely to develop complications, like blockage in the intestines or damage to the intestines. Therefore hernias should always be repaired. Although the condition is not dire, you should get it operated sooner rather than later. If it is not a hernia, but some other mass, it is probably even more important to get it removed.