Snake is wheezing

[sam4snakes]

I have a Brazilian Rainbow, but I post here because no one ever answers in the other boards. He was wheezing earlier in the summer before I went off to school so we got him treated for an Upper Respiratory Infection. While I have been off to college he has been moved into a nice new enclosure and has become very active now. I just got home for the Thanksgiving break and I noticed him wheezing again. Has anyone ever heard of a snake just having a wheezing and still being healthy? I mean he is active as far as I can see so he doesnt appear to be sick. I am just wondering if he may still have that URI. We took him to a vet the first time and he gave us shots to give to him ever like 3 days and we did that but I am just hoping he doesn't still have the URI.