Uh, my snake is "whistling"?

My adult male corn is making a semi-quiet whistling noise with ever breath. He's not clicking or "hissing" at all, no mucous in sight, so I'm not suspecting a RI at this point. He often makes a noise which sounds like a breathy hiss just before shedding because the loose skin around his nostrils seems to irritate him, but I've never heard him wheeze or whistle before. I'm not totally sure if he's in shed or not (because he's a snow). I'm usually really good at telling when he is in blue or not, but its possible I missed the entire blue stage and he will be shedding very quickly.

He also is being a pain in the butt right now because it is spring and as usual, he is in a desperate search for a female to mate with (something he will not soon find), so he's been SUPER active in his viv for the past couple weeks. As a result of this he has a couple very mild abrasions and bent up scales from rubbing the screen top and his hides and such. I can't really imagine any way this activity could have had an affect on his breathing, but I thought I would throw it out there. The scales on his head and around his nose look totally normal.

Thanks everyone!

Could be a tiny piece of shed stuck in the nose.