hey Dawn !!!!!!
about the heat shield, he probably overtightened the clamps. i assume he tightened them to alleviate the problem but probably stripped them out in the process (very easy to do). i would take one off, and go buy some new ones. take it with you to match up at the store. your local or chain hardware store should have them, or an auto parts store. replace them all just don't overtighten them. good luck, they can be a pain to get to stop rattling.