I would go see a doctor. When my friend (and my recipient) started having kidney problems, it was a whole plethora of problems. She had a couple of kidney infections, she was sleeping 16 hours a day, she was loosing hair, high blood pressure, she lost a bunch of weight, she started having vision problems. - there was a lot going on. I know you're worried, but if you had a problem as serious as stage three failure, I'm sure you'd be a very sick person.
The sharp pain may not be coming from your kidney. If it's in your back it could be your hip or your spine. I have a problem in my lower spine (old man back disease) and it hurts very specifically where my left kidney used to be. If I still had a kidney there, I would be worried about it.