Welcome to PT!
It sounds like she could have a UTI.If it persists i would take her to the vet to get some medication for it.
Pedigree isnt the greatest food,full of by-products and fillers.But if she's doing fine on it,then keep her on it.If you are interested in feeding her better kibble,there are quite a few of great food to feed her.Mine are on Nutro Natural Choice.Mine used to be fed Pedigree,but Kodie developed allergies to something in it,so we had to switch him. I dont know much about the BARF diet though.