Skinny...but with a bulging stomach.?

So I'm skinny right. Often when I hug someone they tell me that I need to fatten up. The problem is that while I have skinny arms and am quite bony I have quite a large stomach, it bulges out quite a bit. Nobody ever notices it though because I'm constantly sucking it in and tensing it. So what I want to know is how can I get rid of that stomach (obviously by eating less and exercising more) and then gain weight again but this time distribute it over my entire body.