A metal noise from the right back side of the car while driving on rough surface

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Dear helpers, I need a help please. When I drive, every single shake, hump and rough surface where car will shake, a metal sound like as if a thin light metal is hitting another metal and making a tin tin tin noise depending on how hard the surface. It is coming from the right back side of the car. If I will drive harder on a hump it will shake and make louder noise. What do you think this could be? Thank you a lot