Hi. I am 23 years old female, had my annual physical in February 2016 everything normal only little lowered vitamin D. I have been experiencing shortness of breath, feeling like there is always need to take deep breaths or yawn to relax. No cough, no chest pain. Have seen a cardiologist , did every kinds of tests everything came back normal. Also, have a chronic subjective dizziness. Had shortness of breath but not as much before the annual physical. Is it stress/anxiety related or should I get lungs checked?