I have RLS and I had no idea what it was until a few years ago. It's not "the urge to run" or a twitch. For me it's a horrible pain that you feel can be relieved by writhing around. It's not so bad now, but when I was a kid I'd wake up in the middle of the night screaming and crying and in complete agony.

Like Eli,I find the more active I am, the more physical work I do the worse it gets. It also seems to happen when I've been drinking.