Sherlock:
It is possible that your sound could be an exhaust leak, as the Hemi's are notorious for broken/loose exhaust manfold bolts.
There have also been a number of issues regarding a ticking sound at start up, as well as another noise considered to be a "normal" sound for these engines.
My 04 Hemi Durango does make what I would described as a soft ticking noise during normal operation. While I have not listened expressly for it on my '14 Hemi Charger, it would not surprise me to find it.
A ways back, a neighbor in the market for a Hemi Grand Cherokee invited me to tag along. We ended up driving a '14 JGC Hemi RWD with less than 200 miles on it. When the salesman pulled it around from behind their building, there was quite the loud lifter tapping sound. We inquired about it, and were told that it was "normal" for a late model Hemi engine at start up after sitting a while.
We got in, fired it up, and the sound which was quite alarming for a brand new engine went on for another 30-60 seconds. We took turns driving it for about 15-20 minutes without hearing the sound again.
The sticker on this JGC was $40K plus, and only RWD. While I am indeed a Chrysler/Dodge fan, there is no way I would accept that such a sound was proper on a brand new engine! Yours at 31K is still like new, so I would look into it while under warranty.
Don