What Causes Bulge Under Lower Ribs?

I can feel a bulge and push it under my lower R ribs almost over to my side. I have had a Ct abd/pelvis which was normal. Exam lying down is negative. You can only feel bulge and push it under ribs while standing. Certain positions when I sit makes it feel like "my rib is poking something or a bad side ache". Pain goes a way when changing positions. My doctor feels it is a benign process but it is still concerning. Can it be a hernia? Or any other ideas? It does not hurt to push on bulge. Bulge is not visible but only felt. I am only 5 ft and 95# and it still is not seen.