should my car be having problems with the struts with only 68,000 miles?

What is your question?

I hear a loud thump on my rear right of my car every time I go over a speed bump which I believe may be the struts.

What makes this problem better or worse?

I hear it when I go over surfaces like speed bumps

How long has your 2015 Lexus IS250 had this problem?

a few weeks