When i start moving from a stopped position, i get this sound from behind me. It sounds like metal vibrating and its only for a second. But either way its annoying and its been happening more. Should i take it to a honda place since its still under warranty? Does anyone know what that is?

 

Immediately.

Could be your exhaust coming in contact with something due to engine torque on take off but if you've got a warranty USE IT. It could be something else.

 

While I doubt this would happen on a new car, the family Civic here recently got a new exhaust pipe in front of the muffler, and that same sound was happening. I took a peek under, and the mount for the pipe was way too far up. The rubber hanger was horizontal, and the mount was hitting part of the frame. Good shop eh?

I bent the mount into a more proper shape to fix the problem, but if it's under warranty, let Honda deal with it. Make them earn their bucks

 

Well if you have an exhaust on your car it could be a loose baffle inside of the muffler.