I noticed my tub wasn't draining as it should. I have a basement and after observation of the pipes, I noticed that when I take a shower, the water fills up the pipes and overflows out from underneath the toilet into the basement. I'm guessing that the main line is clogged and that is what's making it come up from underneath the toilet, because it runs to the same line the tub does. I've tried Drano, plunging, Liquid Lightning. I even pulled my toilet up and ran a snake about fifteen feet down the pipe, but still did not unclog it. I reached a wall with the snake but could not tell if that was because of a clog or I just couldn't get around a bend. My next move is to call a plumber after this. Any suggestions?

I even pulled my toilet up and ran a snake about fifteen feet down the pipe, but still did not unclog it. I reached a wall with the snake but could not tell if that was because of a clog or I just couldn't get around a bend. My next move is to call a plumber after this. Any suggestions?
The fact that water comes out past the wax ring tells me that your blockage's downstream from the toilet, otherwise I would recoment snaking from the tub waste and overflow. You either didn't put out enough cable or you couldn't get past the blockage. Try again. You don't have to pull the toilet if it's easier to snake from the lavatory roof vent. Good luck, Tom