BLUE TONGUE SKINKS

I’ve had my baby bluey, Toothless, for a little over a month now, and he’s been wonderful. However one thing that has been concerning me for awhile is his breathing. He appears to breathe rather heavily, different from huffing because there is no noise to this breathing. It happens inside and outside his enclosure, and he breathes like this while sleeping too, so it is not likely linked to stress/seeing me either. Here is a video of his breathing:
https://youtu.be/wNBEE7k4lI8

Cool side stays around 77°F (25°C) with humidity ranging from 45-50%. Warm side stays around 90°F (32°C) with a basking spot at 105°F (40°C). His substrate is cypress mulch (he loves to burrow), and he’s on the Nutro grain-free dog food. Both his urate and poop is healthy. He gets calcium supplements every other feeding, and gets his multivitamins once a month. He’s only been somewhat lethargic the past two days (sleeping most of the day, tends to close his eyes often like in the last clip of the video), but that changes as soon as I take him out. He’s very active and loves to explore and climb up shoulders.

I just want to make sure my boy is as healthy and happy as he can be, but I want to be sure to have a good reason to see the vet if need be. Any and all advice would be much appreciated, and thank you!

RI's aren't too common with Northerns. I personally wouldn't suspect that. I do think it's stress, even if it appears he's sleeping, he may not be. You could set up a camera and see if that behavior is present when you're not filming from overtop.