Do I have a pinched nerve? Or what?

I keep getting a pinched nerve or something on my neck and I can't tilt my head to the left at all and I can turn my head a little less then half to the left. It has happened to me already once during the soccer season (fall) and I look like a idiot with my head ****** to the right. Why does it keep doing it? All I was doing was sitting and it felt like it tightened up and I took two prescribed pain relievers and it didn't work yet....any help is appreciated