I too have been experiencing the same problems. It seems like every time I yawn. I get a deep breath in, so I try to yawn as much as possible when I push my hands on my legs to straighten my back sometimes that helps when I lay flat on my back, it really helps except for after I eat I just underwent a hiatal hernia repair surgery for my hiatal hernia however, it feels like it’s starting to return like like my esophagus stops me from fully expanding what needs to expand I’ve been through so many tests and they all say everything looks normal. It’s driving me crazy it’s good some days bad some days but it’s always bad after I eat I was 205 pounds and a YouTube influencer and have now lost so much weight that I don’t even feel like going back to the gym. I wish there was someone out there with some kind of answers. I think some of it might be related to my spine. I also have a degenerative disc disease and it feels like that spot that pinches is right where everything is stopping me from taking that deep breath. I had a high hernia that went septic and got so bad. I was bedridden for almost 2 weeks and I I tried drinking a bunch of water and that seemed to help a lot more than not which is why I thought it was my hiatal hernia. I’m still eating liquid foods little bit at a time because of my surgery and I’m waiting to talk to someone about my spine like some things pinching something that is important enough that it won’t allow me to take that deep breath or get the fulfillment of a deep breath when I feel that my body needs it but again when I yawn I get a deep breath. Every time every doctor has said everything was normal and looked at me like I was absolutely mental. I’m gonna try those breathing exercises you mentioned, but if there’s any more answers or anything, you’ve come across that would please love to know I’ll share anything I can with you that has helped me Maybe we can connect at some point and talk a little bit more. I would love to know all the information I can thank you for sharing.