Oh my word that sounds horrible, hope you're having an ok day with things generally and not feeling too bad.

I've heard of CRPS in the stomach, but know nothing about it I'm afraid. There should be some info about online - if you've got it in your stomach tho, I'd think it could cause those problems all by itself, however I know from my own problems with meds how badly they can affect your whole gastro system. I had to stop mine after bouts of gastro pain and sickness, liver and kidney function tests ok but pain doc said my meds were known for causing problems.

Also, I know there are some who believe its not a coincidence that so many with CRPS are either coeliac or have other auto-immune issues. I am a coeliac myself and I know how sick I get if I eat any gluten. Might be worth trying a gluten free diet for a while and see if it helps at all.

Sorry I can't help much, hopefully you will get some answers and a way forward soon though. Good luck with it

Bram.