Baby randomly has a hard time inhaling?

I want to see if anyone has had a similar issue with their baby. This is not life threatening (although we thought it was and went to the emergency room) and we’ve consulted and visited with pediatrician already.

Our baby is 4 months old male no prior issues. The past few days he would randomly have trouble inhaling. To best describe it, it sounds like wheezing when he inhales. It happens when he lies on his back or on his stomach and sometimes even when he’s sitting down. It isn’t all day and most of the time his breathes are normal and sound normal. Although I want to think it’s congestion, a lot of times it sounds dry if that makes sense.

We really don’t know what to think of it and wanted to see if anyone had a similar problem before we go down the X-ray/testing route.