H.C.
I read your post and immediately thought reflux/aspiration which in turn causes the wheezing. The arching and grunting is definately a sign of reflux. Sometimes refluxing can go into the lungs (aspiration) and the contents of the whatever he's refluxing causes irration in the lungs thus the wheezing. If you correct the refluxing and in simple cases all it takes is medication then the wheezing goes away as well. I'm a pediatric healthcare provider and this is a common problem. Tell your doctor you suspect reflux and go from there. Good luck. : ) And in the mean time, you may want to elevate the head of his crib too.