When I vape, I often get kind of out-of-breath. I vape various juices and have not correlated pg/vg ratios to problems though that might solve it. Also, ever since I started vaping at night it is harder to breath. More and harder congestion in my nose. One final thing is after vaping a while I often have a weird spasm in my chest, low near the top of my stomach, I think it is my esophagus gently spasming. Nothing I can't live with, but weirdly unexpected. And remember I quit smoking 4 years ago, I just vape for the fun of it.