I wouldn’t call it shortness of breath because I can breathe normally and comfortably but every now and then I get this urge to take a really deep breath or yawn?

But when I do, the deep breath in isn’t satisfying and feels like it’s not reaching all the way down into my lungs/belly...It’s a very odd feeling. 

The doc checked my heart with a stethoscope and EKG and everything was normal. 

Could this just be anxiety or should I be worried?