dog's bottom seems to bother her after pooping or peeing?

It seems this is an on and off occurrence for my dog that after she poops or pees she sits down immediately, mostly after pooping. i can't pinpoint which it is. it's been going on for years and all vets continue to say they have no idea. i think it's really bothering her. she comes in the house and has to sit down with her bottom backed up to something for awhile. Vets have check for urinary tract infections over the years and she has had slight cases of that but nothing extreme.
Can dogs get yeast infections or hemorroids?

They sure can!

This may sound grosse but what is the consistency of the stool when she is bothered by it?

Yeast infection would show up in urine sample so if she is okay that way it could be something else.


Is she spayed?