Im 22. It's been more than year now dealing with shortness of breath/over breathing. It started with panic attacks. blood test and ECG done which came back everything normal.
this shortness of breath comes maximum time at night before sleeping. After good sleep it usually goes away. It also hard to sleep with this.while it's going on It's really hard to fix it and get into a natural rhythm.
if i focus on breathing it get more worse. So i try not to focus on it. But it's really hard to do that. i just can't take this anymore 
I’m right there with you. I have been suffering from shortness of breath for about a year now. I get super tightness on my chest, I gasp for air . I sometimes get this weird sensation of numbness or like frozen chest where I don’t feel my chest expand. It’s terrifying but stressing over it makes it worse. I have learned to keep calm and not panic. Deep breathing techniques can help. I also breath through my mouth which helps. Stretching my hands over my head helps too. Just stay calm, practice meditation and breathing. It won’t solve the problem but it helps to ease the anxiety. Anxiety is a b***h and unfortunately you have to learn how to manage it.