Shortness of breath - feeling like I can't catch my breath

I don't have that specific issue, but most people would just call that anxiety.
So many people in their 20s are dealing with this lately. The internet is flooded with stories from people sharing their experiences and how they manage it. Apparently, you can't just switch it off, but you can dull the edges by changing your lifestyle habits. Eventually, it fades.
It wouldn't hurt to read what others have gone through in similar situations, but you really should check in with your primary care physician.

Dealing with the exact same "issue." It’s been dragging on for a while now. I'm 27. First time I felt that choking sensation was when I was 19. It lasted for a bit, felt terrible, and I went through every medical test imaginable. Thankfully, my body was fine, so I knew the "suffocation" was purely psychological. I eventually started ignoring it, and the feeling vanished. Didn't come back for years. Then, out of nowhere, it's back. Started in December, just a few months ago. It hit me suddenly—just this feeling of running out of air, even though I wasn't even thinking about it. Since then, the fear took hold, and everything spiraled. I shut down so hard I fell into a depression. I don't even recognize myself. Panic attacks, agoraphobia... especially around the holidays, if I did leave the house, I needed my parents to go with me. I don't remember being this version of myself. I used to be strong, independent. I honestly don't know what happened. But I realized early enough that isolating myself isn't working. I have to force myself to face the fear. Realized how much damage you can actually do to yourself if you just let it happen... It's a disaster. I saw a psychiatrist and a psychologist. They told me it's anxiety caused by bottling up frustration. They're right, but I don't know how to actually let it out. Anyway, I have an appointment with a psychologist in about ten days, so we'll see. And btw, I'm refusing any pills or antidepressants. I'm not going there. I believe you can fix this naturally if you just have enough willpower.
But the constant shortness of breath won't quit. Especially when I'm resting; it's because I start overthinking it. I've noticed that when I stop focusing on it, I function normally.
It's easier when you share this stuff with others and help each other out. Keeping it all inside is never the answer.