Is it normal i have a habit of rocking back and forth?

Ever since I was a teenager, I've had a habit of rocking back and forth in my seat. I even do it while I'm driving. I do it the most while listening to music or while in deep thought. The rocking started at around 17 or so, but was pretty much only when I listened to music while I was sitting on my bed. I started doing it in the car at around 21 or 22, I think. It's a very ingrained habit now and I can hardly sit still. I only do it if I'm by myself and in deep thought or listening to music, though. My best friend has caught me starting to rock while I was driving, however.

I also used to rock side to side as I was standing, but don't do that as much anymore.

I've always been pretty energetic and some part of me usually has to be going at all times; my mind, my foot tapping/leg jiggling, rocking, my hand tapping/ticking, etc. That's another weird habit - I tap my index finger and thumb together with my right hand when I'm thinking, usually spelling. I'm visualizing writing the word.