Clunky flute mechanism...?

My flute is a Pearl 765RBE-CODA Anniversary model, which I have had for about two or three months now. Though it was sold to me as new, it was a store model before hand, and I'm not sure how long it had been in there. I've recently noticed that the mechanism has become heavy and clunky, not only with the feel of it, but I can hear the keys as well when I'm playing. It wasn't like this when I first got it. Is this fixable? If so, what needs to be done to fix it, and what is the average pricing to have it done?