Tummy Troubles

At the most random times, my stomach will cramp up and hurt like no other. It feels like there’s a lot of gas building up and sometimes it gets painful to the point where I can’t stand up straight or walk. My bowels have also be strange lately. It’s either diarrhea or I’m constipated. It used to happen very rarely, but now it happens at least twice a week. A lot of my friends say I should go get tested for Crohn’s Disease, but I feel like I would be in a lot more pain if it was that. I do drink, but this started happening when I was 19. What is it?!