Does anyone know what needs to be done to fix this really bad rattle I have....It comes from the driver Side shoulder/head area either where the seatbelt housing is or the actual rear quarter window. The only thing I can do to get it to stop is by pressing fairly hard against (outwards) the DS quarter window while inside the car. It also seems that this windows moves slightly when pressed on...at least noticeably more than the passenger side

Is there something I can do to fix this? I know others have had similar rattles but the search turned up too many "rattle" posts

any help much appreciated