I have the same problem, I'm a mouth breather. I did see and ENT specialist (Ears, Nose, Throat) and was told I just have a really small nasal passage, although I do wonder about the deviated septum thing. I can breath through my nose if I sit and make a conscious effort, but I don't get enough air and eventually take a big gulp through my mouth. It feels like the air from my nose (when I breath through my nose) isn't filling my lungs, or even going to them and I feel like I'm suffocating. I am sorry I don't have any advice, but at least you know you're not the only one
