Some kind of metal dragging sound?

[kyokuncatlover]

I started hearing this noise after I drove on a freshly oiled and chipped road. It sounds like metal being dragged, but I checked under the car and there is nothing hanging and touching the road. I never had this problem before and I only hear the sound when I am moving forward, not when I am moving backwards. It still feels like its driving the same. What might be the problem?