I would have have my gullblader checked and if your sytomes are triggered by high fat foods theys tend to be give aways even if you alredy were checked theres always a chance they have missed it. If you have deffintly ruled that out you appendix are on that and all the doctors seem to be unable to find any thing I would check into a nerve study sometimes do to previous operations you could have damage.I 'm sorry for your pain.
Lisa C