When my kids were little, my wife started having intense shoulder pain. She had been painting walls in our new home, and she kept lifting the heavy paint cans with her palms facing down. That night when she explained the pain to me, we got her some ice to help reduce the pain. (See our blog Heat vs Ice for when and how to use ice properly.) I then showed her a tip to avoid injuring herself in the future by lifting the paint cans with her palms up.
It's second nature for many of us to lift things up with our palms down, like if there's something you need in the back seat. If you find yourself needing to grab your purse or a diaper bag from the back seat, turn in your seat and lift the bag with your palms up. You'll help avoid injury of further injury to your rotator cuff. As I show in the video below, always lift with your palms up to avoid injuring your shoulder, specifically your rotator cuff.