We can't tell you anything until you tell us your history. That means we'd need to know when the problem began, anything unusual before it began, and what you think it may be. It is unlikely that the problem came with no reason, and therefore, there must be an explanation for your problem.
You can go to a doctor, but I think he/she may not be of much help unless you give them something to work with (information for them to do something).
If you feel comfortable, tell us more about it.