You are going to have to share a lot of information to get help Matt. Mapping and doing things with Google Maps as you describe can be VERY complex and there are many ways to use pins.
You created a map, did you do this using
https://mapsengine.google.com/map/ or did you create it as a static Google Map or as a Fusion table map? It makes a huge difference in which path you need to follow to accomplish your goal.
Show a screen capture of your blocks and ask a specific question and you should get some advice. Be aware, what you are attempting is VERY difficult to do all the things you want with App Inventor 2. Google has a Business Map API ...you might be able to use that and ActivityStarter to do some of what you want...you have to pay to use the Business API. Are there ways to use pins without the Business Map API? Yes, and you might be able to some of the things you want to do with AI2.
To do all of the things you want to do, you should be coding with a professional, compiler; like the Java based, free Eclipse or Android Studio. These tools have established libraries for working with maps. Can you code something with AI2, certainly.
Regards,
Steve