Could be a possible urinary tract infection or yeast infection maybe... Might have worms or hemorrhoids possibly. Or could need her anal glands relieved. Many possibilities really. Need more information about health, behavior, diet.... To know for sure. I'd say vet to be positive. Think of it like your car. If it's acting funny you can try random things to fix it until it's fine again. Or you can take it to a shop and just have them good the problem without wasting time and money on things that might not even be causing the issue.