When I turn right, my car goes thump and the same thing when I turn left. What is this?
The dead body in the trunk?
Seriously, that’s not enough info to say… what make/model/year? Mileage? Does it do this only on sharp turns or any turn? Low speed / high speed? Does it do it only when the pavement is rough? Does it do the same thing when you hit a bump with just one tire, or say a speedbump at an angle?
Checking the trunk isn’t a bad idea. It may be good to check the unsecured spare tire to see if it is floating in a puddle of water. After you find nothing rolling around or surfing, as well as no bottles under the seats, you can have the ball joints, tie rod ends and CV joints checked. Then there are wheel bearings, lug nuts and struts.