How old is he? Does he have things to climb on? A log or "tree branch"? Do you take him out at all? Is there enough ventilation and air flow?
Did he eat a live mouse? Are you offering too big of prey? Does he have fresh clean water?

If it's none of that he may have a respiratory infection and you should take him to the vet. The wheezing and mouth thing worry me if he's not hungry. Definitely try smaller prey f/t if that's what you usually use.