Could My Diet Plan Be Affecting Abdominal Pain?

I desperately need to know whats going on with my body, for the last 4 months i ve been very active and have unfortunately dropped out of my weight range, I m trying to get back into it but I dont want the fat ass swollen facei had before, my current situation is this, just recently I havent been able to work out due to lower abdominal pain, mostly burning. I dont know what caused it or what is causing it but it gets worse with the more I eat, and not being able to work out is not an option for me because I can see fat forming on my lower stomach and face, and that in and of its self is very frustrating to me, and here lately, especially today I ve wanted to work out but havent been able to for fear of my stomach starting back up that and I just feel out of it, I m maybe 150 with a large frame at 5 10 so im well out of my weight range. and I know I have to gain some fat to gain muscle, but im gaining fat in the places I dont want to gain it in, long question short, what in gods name do i do? all thats in this house hold to eat is bogged down with saturated fats, empty carbs, sodium and sugar.