I have a 2007 cadillac dts, I needed two front tires and when I went to get them they put my car on a host and my wheels were hanging, and when i left my back shocks was not working and hitting hard

Look at your shocks. If they are leaking or covered with dirt like they were wet. Then when you had it up on the rack, there is a chance that they were pulled apart to far. Now there is no fluid left in them. They are so easy to replace that it,is really a DIY job.

So do I have to replace my shocks?

If the shocks were broken then yes. If they were original to the car. They were probably due for replacing.

I agree with dsppspc13. Good chance your shocks were already failing and the stress of being on a lift and hyper-extended was the final thing needed to complete the failure.

WHAT KIND OF STRUTS AND/OR SHOCKS SHOULD I PUT IN

ont have an answer thats why iam writing to you!

stock air shocks