"Itchy" or restless muscles?

I've been running more lately (5 mi yesterday, 4 mi Wednesday, 9 last weekend for my long run) in addition to squats and deadlifts. I've noticed that on my rest days my glutes, hamstrings, and calves feel restless... It's worst in my hamstrings. The only thing that makes them feel better is like isometric tightening or otherwise working the muscles.

Is this a thing?