iphone screen freezes or goes dark since IOS 8.2 update

Installed the 8.2 update on my 4S a couple weeks ago and since then my screen keeps freezing (no touch capabilities) or it will go dark. When this happens the phone won't even shutdown with just the power button and I have to do a hard restart. The battery % registers at 80+% but after the restart it will always say the battery is dead and i need to recharge my phone. does anyone else have these problems and have any suggestions?