As I was running errands, I found a spot kinda late, and I braked and turned hard to get it. In the middle of doing it though, my steering wheel locked up. I restarted the car and it unlocked. Any reason why it did this?

Did it lock up because the engine stalled? If that'* the case it didn't lock, you just lost power assist.

The engine did not stall

It'* possible the power steering pump is going out. Did you check the fluid level?

No I haven't had a chance yet. That would cause it to suddenly fail but work again when restarting the engine?

It'* possible if the level is at just the right level that the fluid stopped moving.