I have no clue where to start.

I have a 2 story house and about a month ago, I notice the ceiling in the Kitchen getting a little damp. No drips. Over time the ceiling began to crack. This is a new home I purchased 3 years ago. The only room or area above the kitchen is my bathroom.

It is a standing shower. The toilet and sink works fine. But it "appears" when the shower is being used, more of the ceiling in the kitchen gets wet.

I have checked for any cracks. Check the sealant for any leaks, none. I did reseal just in case. I can hear when the water is flushed or sink ran that those water streams fly by as it sounds. The drain in the shower looks like 12" down and then turns. No idea what direction. It is standing water. in the drain. I have tried draino/plummer liquid. I have tried a 3-4ft snake. Nothing comes out. Tried the plunger recommended on this site.

Since I did not know where to go and not really wanting to pay someone alot to investigate and fix, I started to dis-assemble the shower. I have the glass door off and all metal/alum pieces. The shower handle and cover has been removed. I have no way getting under the shower unless I remove the what appears to be drywall in the kitchen. There are lights there. I thought removing the standing up shower thing I could get underneath and check the plumbing. But the drain I have no clue how to remove.

So, I am looking for some other suggestions or comments in either concerning the leak and how to unplug. Like, do they make longer snakes? Or suggestions in removing the shower. Maybe that is the wrong way to go.

Thank you