or somehow muting myself when I am talking and try to rest the phone on my shoulder. What am I hitting with my cheek and how do I stop it?
am i reading this correct? you have the phone rested on your shoulder? this might be your problem, by resting the phone on your shoulder and against your check, the phones sensor (located in the upper left portion of the phone) is probably receiving some small amount of light which turns on the screen then your cheek presses the mute or end call.
have you tried the other shoulder, the sensor might be covered up better?
or press the power button as you are about to talk, sometimes i do this and it keeps the screen from turning back on.
or, just hold the phone with your hand instead of your shoulder (or use a bluetooth device)?
there should be an app for your problem too, i remember seeing it but cant remember the name right now.
I think you are experiencing a feature of the phone which, based on how you use your phone, is a quirk for you. Same for me, BTW. I suggest that you download the app Screen Suite.