I had a similar problem recently. My ball made some strange wheezing noises, leading me to believe he had an RI. Well, temps were fine, humidity was great, and no bubbles were visible. I realized the loosening of skin in his nostrils was causing these noises which were only heard when he was held. I stayed cautious though and after he shed about 2 days ago, the noise was gone and he is fine. Hopefully, your snake is in the same situation.