I've had it since I was a kid. I know this sounds silly, but when I was little and didn't know what it was, I thought it was because my legs wanted to keep dancing (I was a competitive dancer). I never told my parents about it because I didn't know there was a name for it or that it was a problem. (Other than being really annoying and not being able to sleep.) have
I have a very hard time with any long periods of sitting because of it. I used to have a three hour night class where we all sat in a circle and it was torture because I really needed to move and jerk my legs but it was embarassing because everybody could see me. I tried so hard to suppress it that I couldn't concentrate well. Just this past weekend Aaron's sister was asking me why I kept jerking my legs in the car when we went to Nebraska for their grandma's funeral.