I hesitate to say what this could be but it really sounds like something a doctor or therapist should help you with. So far it does not sound like anything too serious but it could easily grow to become quite problematic so if you saw someone about it now you could possibly save yourself a lot of grief in the future. Not many of us here at PC ever had that chance and look where we are now.

It is very unusual for me to recommend seeing a doctor or therapist with out offering some type of advice first but I would just like you to have the chance to nip this in the bud before it develops into something worse and long lasting.