I am 28 years old and I'm having the same problem. It happens on and off can last for weeks, couple days, a month. I would say it's been going on for probably at least six or seven years maybe even longer.
Like I read that someone said it's shortness of breath accompanied by yawning or sighing or even feeling the need to burp sometimes I guess to try to get air, I'm not sure.
When I try to take a deep breath it's like I can feel my chest getting really tight right before a deep breath would happen and then it doesn't happen. After a while of trying and not being able to get a deep breath it starts to really starts to become an issue. If I do any kind of work or physical activity while this is happening after like 10 minutes I feel exhausted and like I need to take a break and of course yawn and try to take a deep breath but I just feel completely wore out and of course, out of breath. I don't know how else to explain it. If I'm doing something physical then I feel like it kind of helps me keep my mind off of it so it's not as bad but it still continues to happen. But then if I like lay down or sit down for a long period of time I feel like I focus on it more and it makes it even worse and it makes me want to freak out. If I lay down it makes it even harder to try to believe because I feel like my chest is heavier or something. This it has happened continuously for long enough that I've went into full-blown panic attacks on multiple occasions.
I don't have allergies I don't have acid reflux I don't have gerd I don't have sinus problems or anything like that. And I do have depression and anxiety but I feel like for some reason it might not be the case. Cuz it happens even when I'm taking my medication. But I feel like even if it was the case it would only happen when I'm having an anxiety or panic attack or maybe hours prior to that or hours after.