I think I pulled a muscle in my back?

Yesterday when I sat down my lower back got a really bad pinching feeling all the way down in my right leg. I got up later after It stopped hurting so bad and it was ok but when I bent over later I got the same feeling only I couldn't stand back up I had to have help. I have a softball game tonight and it's very important I be there I'm the only catcher we have.. So what I'm asking is do you think it's a pulled muscle or pinched nerve or what do you think it is and what should I do about the game tonight?