I'm 33 years old and when i was in my 20's i abused alcohol, lately whenever i have a drink socially i get the worst pain in my stomach. why?

Irritation: Regardless of what you did in your 20s, it sounds like your stomach is telling you something! i would worry about direct irritation called gastritis, or even ulcer disease. Drinking socially is of course something that needs to be explored as it can be a lot or a little. With the pain being so severe, it would be good to talk with your physician, especially with what you shared of your past use.