Engine will not turn over?

Hello,

I went to move my car the other day and it slowly shut off while moving it. It turns on and the engine will crank twice but then I hear a bit of a grinding sound and a burning smell comes from under the hood no smoke though. Not sure what it could be. Thanks in advance. I'd like to add that I did have trouble accelerating uphill and when I first start the car for the day it was like someone put a few bricks in the engine but after a while of driving it was fine.