Took off exhaust and now funny noise under passenger side

I took off my exhaust today all the way up the the caty. It don't sound good but still better than the Flowmaster I had, at least IMO. Driving through town afterwards I heard a funny noise coming from under the front passenger side of the truck when I stopped at a light. I wouldn't call it a 'ticking' noise; a combination of ticking and rattling describes it better. It only does this when idling though. Any ideas?

 

one time i took the front left wheel off of my truck and when i drove with it off it pulled to the left.

 

Baaaaaaahahahahahahahahah!!! I just cried so hard!!!!

 

You could put a muffler back on and see if it goes away

 

Heat shield still in place and fully attached?

 

Yep. I might have made some contact with the shield but no bends, dents, etc.