Scroll Wheel won't turn

I have a silver 8GB fuze. I have had it for about a year and a half now. The scroll wheel just recently acquired a problem rotating, I have to use two fingers on opposite ends to turn it. I have tried to clean the wheel, it will rotate smoothly for about 20 minutes before being almost imposible to rotate. Another note, if I lay the fuze on its face for a few hours it will rotate smoothly, but as it rotates I feel a point to where there is more drag than other parts of the wheel, then again become extremely hard to rotate. I recently dropped it on its face, I am not sure if it is the cause of this problem. Thanks for any help!