I agree with Astray. Go have it checked out. If you have no money get in touch with free clinics or social services in your area as a start.
You will need to tell the examining physician about the things you were taking and I know that is hard. But a doctor is a doctor and needs to know all the things that went into your body that could have caused it harm.
Good Luck. Let us know how this turns out.
I think you should get a doctor to check/scope you, its not unheard of for abuse of pain pills to cause GI problems. Its probably nothing serious but if you do have a tear or infection in there somewhere and you ignore it could get serious.
YOu know I have the same thing happening to me now and I am not w/d been on methadone 2 yrs now. But most morning I wake up my stomach is sick and I usually throw up and mine is also orange yellowish stomach acid. I take zantac daily 75mg-150mg and helps during the day but not morning. I have not always done this just started about 2 mos ago. I just thought I had a bad stomach but you have it also wonder what really is??? There is some stuff that I cant eat bothers me to bad.