I have the urge to pace (walk back and forth) whenever alone

When I'm bored, upset, feeling contemplative... wherever I fit on the continuum of moods, I get the urge to walk around, often back and forth in circles or in straight line patterns in my house. I do this on average from 10-30 minutes a day, and I don't do it at all when anyone other than my family is around, in fact, I prefer to do it when nobody is around at all.

9 times out of 10, I pace when I listen to my ipod, and I start pacing faster when I get into the music, and will even run up the stairs if I get excited. I will also do it while I'm studying notes, and the rare times when I have long conversations with people on the phone.

I'm not 100% aware that I'm pacing sometimes because I'm often reflecting on various matters in my life. I'm usually in a daydream, but not too deep that I can't snap out of it. My family will point it out sometimes, but I often realize I'm doing it before they tell me. Friends and roommates have caught me pacing before and I felt embarrassed. My family doesn't care as long as I'm not 'hovering' around them or making noise late at night.