A couple days ago I pulled out of a parking lot and in order to go out the side walk was really low so I felt my car scratch and bump a little. I didn't think anything of it considering I have accidentally scratched it from time to time. But since then it has been making a loud sound towards the front of the car and you can only hear it when you are in the car. Once you start it up and even when accelerating it sound like a loud rumbling sound. Possibly the muffler, i don't know? anybody help?