I Am Going To The GI Tomorrow And Want To

I am going to the GI tomorrow and want to make sure I ask the right questions. Ive experienced nearly constant digestive tract pain for a week. It subsides when I fast. I am having difficulty having any BM without a laxative. After 3 days a laxative I was prescribed from a different GI started working, but I felt it was also causing me stomach pain. I have more gas than normal after I eat most foods or feel full. I think I may have crohns disease or ulcertive colitus, or maybe a bacteria or virus from improperly cooked food I ate. I already have celiac disease. Are there other diseases or causes I can consider when trying to determine what this is? I already gave blood to test for Crohns. What other tests should I do?