There was a recent thread where some people said that various strange sounds can result from a snake having a bit of shed in its nostrils. So if your snake is about to shed or just shed but might have a bit left behind, that is something to consider.

Also I've had the experience with human doctors where I went in with a very small problem (or with my daughter with a very small problem) and they told me it was nothing. But I knew myself/my daughter better than they did, and it turned out it wasn't nothing and in a day or 2 I was back (paying for another office visit) with the same problem, just that it had gotten bad enough for the doctor to recognize it.

So you might want to consider those things before you dash off to the vet at the first popping sound that you hear. $38 dollars isn't much to pay just to be sure that your snake is healthy though. I'm definitely not advising against going to the vet.