Question about my new diamond python

[Reptilegal]

G'day all!
So I purchased a GORGEOUS 4yr old diamond python 4 weeks ago, and sometimes when I put him on my shoulders and he is close to my ear I hear a faint quick 'whistle' when he breathes in or out. It doesn't happen all the time but I'm a bit worried it could be a lung infection?? His hot spot temp during the day is 27-32 degrees celciuss and his night time gets down to maybe 18. It's autumn now and it's very cold, night time temps outside can get down to 5 deg celciuss. He is eating eagerly very 1 1/2 weeks, he hasn't pooped yet since I got him but I heard it can take a little while for them to poop and if he doesn't within 2 months I will soak him in warm water. Am I doing everything ok?