In my opinion doctors often guess at a lot or may say something like that, they can’t see by looking at it - but it’s your body and you know it best so def take the initiative and look into an elimination diet. Even if you tried it for a week you may find it helpful. Pro tip, elimination is total elimination, not less of or reducing (i.e. no bread, no sugar, etc.) It can’t hurt if you’re out of options, I hope you get some relief soon!