Its most likley not the stoma, but the skin around the stoma. In fact, your intestines dont have nerve endings, so you cant feel them. You'll need to check two things. First if the skin is broken down around the stoma. Second, if you use convex appliances, that they arent cutting in to the skin. If its the skin breakdown, get some Karaya powder, and barrier seals. You'll need to find a way to seal you bag to your skin better. If its convex and is cutting in, just loosen your belt a tad.