when i accelerate, there's a sound of like metal rubbing with metal coming from the back right side. And i can only hear it when accelerating, if cruising - all nice and quiet.

 

*sigh*....
you need your axle greased.
should be under warranty
if not
~$200
well worth the money...
If you search there are countless threads about this.

 

Hmm...really? I had that done last time, but it would be a different noise and only when I was in Reverse.

 

when i had the axle issue on mine, the sound would happen when i was accelerarting from a stop, and also when going in reverse.

 

axle click

 

Took mine to the dealer for the same problem easy fix linkge bushings were dry needed grease

 

If you have recently had your car lowered or work done to your back rear tire maybe its the heat pan rubbing on your rotor. I only brought this up b/c you said it sounds like metal rubbing on metal. Something else to think about Whatever it is i hope its easy to fix.