Not all pets are painful or lick their vulvas when they have a UTI. Bring her back and ask that they run a urinalysis (this seems CRAZY to me that it wasn't done in the first place, anyway, since you brought up a UTI... any vet here would have been happy to run one for you just to rule it out as a possibility!!!!). I'd recommend against obtaining it yourself as collecting a voided sample can introduce bacteria and can throw it off... unless your vet doesn't obtain sterile samples via cystocentesis.