I suffered of the same for more than 10 years, since my gall bladder
failed and then it was removed.
What happens is that your stomach can't reach proper acidic levels to activate pepsin
enzymes so they can breakdown protein.
You get cramps because your intestine is trying to absorb a molecule that is too big. Therefore the muscle cramps
Most doctor's won't know what you have. They usually have no idea.
The thing that fixed me was Biogest from pharmaca. You can buy online from pharmaca.com (i think, not sure).
If that doesn't work keep trying different enzymes until you find the one.
DON'T give up. It is important that you find a solution to your digestion problems. I suffered of depression
since my gall bladder was taken and it went away once I fixed my digestion problems with enzymes.
Hope this helps