my upstairs shower is leaking down to my kitchen ceiling. I first thought it was the grouting, I re-grouted worked for a couple of days (odd) but then it began to leak again. So I turned on just the bath part and let it run no leaks, then I switched it to the shower and it immediately started leaking again. It also looks like when the shower is running the water is coming out of the back of the bath spout ( where it connects to the tile) Any thoughts and is it going to be complicated or expensive to fix? Thanks!!