2008 Chevrolet HHR rear noise; volume increases with speed

noise coming from the rear gets louder as speed increases could this be a wheel bearing gone bad details

Yes, it could be a wheel bearing. It could be a very worn tire. There is a remote possibility it could be a brake noise In any event, all 4 corners should be inspected. Why? Noises are tricky and can fool you as to their source and direction.