If it bothers you and you can't stop, and especially as you are using it as a way to cope with difficult feelings and tension, you might consider therapy if that is an option for you. You will need to learn some other way to manage the feelings in order to be able to stop. We all have to cope somehow, right? Relaxation techniques can help a lot. There is a thread about relaxation in General that you could check out if you are interested.

Rap