Maybe Obsessive Compulsive Disorder? This involves behaviors similar to an itch you just *have to* scratch. If you try to avoid doing it, it totally consumes your every thought until you give in.
Or it could just be a plain ol' habit. A true disorder is something that interferes with daily living tasks and compromises your quality of life. Most everyone has a quirky habit or two, or pointless little ritual. I have to make sure my glasses are set down beside my bed just so- sometimes I check once or twice to make sure I did it. I used to lose my glasses often, which was a problem bc I'm blind as a bat! So I developed this habit.
One thing I've learned about myself is that every unusual behavior began bc it served a purpose at one time. So I guess you would be the one to decide how much of a problem it is for you. To ask why you might have started to do it.