I have been having issues with my upstairs bathroom. I had to tear down the living room ceiling because I though was a leak.. Ruined my ceiling. So I thought it was a drain pipe leaving so I replaced the part I thought it was coming from. So I put the ceiling back up and found out still leaking.. so I had to tear it all down now everything was soaked. Before it had 2 layers of sheetrock and insulation to absorb some the water. Found out it is a clog I think. Anyway its pouring out underneath my sink from using the tub and shower. And going right down on my living room ceiling. It doesn't have a closed pipe. The pipe from the sink just goes right in the 1 1/2 pipe without anything to tighten. Just sits in the pipe. I'm thinking to buy a screw type fitting so it goes in the sink and not on the floor. But what should I use to open the clog?

Doesn't sound logical, a shower won't back up to a sink drain, not if they are on the same level. All drainage pipe should be sealed. Show us a picture of the piping underneath the sink. Sounds like you have a blockage that is blocking both the shower and the sink. Snake either the shower or the sink. The sink would be easier.

How do you use a snake. I tried using one but can't get it to bend around the elbows... in the floor rafters is a elbow and that's about a foot down from where I start and then after that I have spit about 8" that's from my shower to the main drain pipe.. I'm using a 3/4 snake . I have never been able to use one correctly. This one is a 25ft wire only with a pipe you stick the wire through so you can have a handle.. I like the wheel crank ones.. anyway do you know how to use one?

Basically you push and turn at the same time. Not familiar with what you have. Suggest the type below. You pull out a short length of cable, put in pipe, begin pushing and turning, When you have that cable in the pipe, you pull another foot or so, push while turning. When you hit a bend the turning makes the end of the snake work around the bend. You work as close to the end of the pipe as possible, pulling out a foot or so of cable at the time and pushing it into the pipe, turning all the time.

Where is that pic of the piping under your sink? Show us the pipe that was not sealed.