I have had an ongoing problem with a smell coming from my shower drain. I had done everything to fix the problem myself but had to call in a plumber when it wouldn't go away. Since the shower drain was not clogged, he did not offer much help. He reluctantly snaked the shower drain and nothing came up. I told him I suspected it was a venting issue since I read up on it in this forum, but all he did was go outside and look at the vent (he did not go up on the roof or attempt to snake it). He flushed the toilet and pointed out that a big bubble came out after he flushed it but there was no stoppage. He left me a big bill and nothing to show for it. Last night, I noticed an odd sound from the bathroom and actually saw the toilet emptying itself, with bubbles coming up every few seconds. I flushed the toilet and the bowl filled with water without going down and almost overflowed. This morning, it was nearly empty again. Now I know I have a problem there and I really don't want to call in a plumber but it looks like I have to. I just want to pinpoint exactly what the problem is so I don't get the run around and pay for nothing again. Thanks!