Upset stomach , but is it pouch or old stomach

[trnsmaster]

Had revision to bypass due to Gerd , now get upset stomach but nothing I drink , eat , tums etc calms it down .
Is it the old stomach part that nothing enters causing it and if so how do you cure ?
Thanks for help

 

[trnsmaster]

Thanks for reply
Trouble is I have been asking them , have had cat scans , etc