Alright I just replaced my bathroom sink and faucet had some problems but managed through. Turned my water back on and the went back to the bathroom sink to turn the valves on but they won't turn. The valves are brand new quarter turn Sharkbite stop valves. What could I have done wrong? Both valves are in exactly the same state, they just won't turn.
Based on the above discussion and my own experience:
Turn the water off and twist hard. New ball valves can be sticky, and the house water pressure behind the valve could be making that situation worse.
Apparently this worked for the original poster.
I had this problem and after some playing around I did the following. The tap had a little screw that holds the cover handle thingie that you grip and turn. I undid the screw, took off the handle thingie and then turned the faucet off and on a few times with a wrench on the brass stick. It was just stuck turning the first time. I couldn't get enough torque using the handle thingie. Once I had turned it off and on a few times with a wrench, it was fine and I could then put the cover thingie back on and turn it easily.
One big reason this happens is that most people open the valve all the way open. When this is done, it will cause the shutoff to be stick and possibly leak later in it's life. Always open the value all the way and then turn it back (off) a 1/6 or 1/4 turn so it's not "locked" in the open position.
This pertains to these types of values (if this images showup)