Fridge collecting water inside

The drain is clogged.

If you want to DIY then here it goes:

Some models have access to the drain by an elbow on the outside back of the Ref. Disconnect the drain line here and if you find the clog, great. If there is no visible drain line and elbow on the outside then...

Hopefully you can access the drain in the back top center of the fridge. This will require removing plastic covers, usually a few screws is all you have to deal with. You must get everything removed so you can see the drain hole in the back wall then you can use a tube and a little air pressure to clear the drain from that point down. If this is clear and you don't find any cloggs from that point down then the clog is at the top of the drain which is in the freezer.

This is going to require a little more work.
1. Take everything out of the freezer, put it in a cooler or just pile it in the sink.
2. Take the icemaker out.
3. Take out the back panel so you can see the cooling coils.
4. The drain hole is in the center directly under these coils but may not be visible because of ice in the drain pan.
5. Use a hair dryer to melt this ice and clear the drain so water flows down.