Our dragon has made a clicking noise- only once or twice at night - everything I read says it's an upper respiratory infection- but he doesn't have any Crusties around his mouth, his eyes seem fine, he is about to shed around his beard area......
I can see his breathing but not sure how to tell If it is labored or not..... no gaping just visible breaths.
Sometimes this happens when their noses are plugged from a shed too. If there isn't excessive mucous around his mouth and he isn't acting lethargic I wouldn't worry about it too much yet. Maybe bump his overnight temps into the high 70s for a bit to reduce stress on his body. If his temps are good and he has sufficient UVB exposure I'd wait until the shed cycle is done and see how he is.
It does seem to irritate them, but it's a natural process so it's best to let him be and know he's just doing what he's designed to do. Shedding is a good sign, as it indicates growth and health =)