Last night at work I started to walk and my left leg locked up starting at the front/top of thigh and shot down to my ankle. the pain was so bad and about every other step I took it would lock up. I was afraid I was going to fall. Some of the time it pulled/hurt in left side of my groin. I just kept on trying to walk it out off and on during the evening and it didn't go away until sometime during the night. I'm assuming it was spasms but I have never felt anything so painful. I do take a muscle relaxer at night. Needless to say it scared me.