Hi, i sometimes feel like i have a really short breath and not enough oxygen goes into my lungs. I've tried smoking before but its not often.. Maybe 5-8 times a month max (sometimes not at all). Sometimes i can take a very deep breath and i actually can feel the oxygen goes into my lungs but sometimes i fail. When i didnt get a chance to inhale more oxygen i feel like my chest are tight... Side note: Im 22 years old and im quite overweight but not obese.. Ive been losing weight by eating healthier lately.

This condition has been occur for this past 2months(max) and it get worse at night (or before sleep). But after i fell asleep, i woke up feeling fine and no more shortness of breath. Any idea what this is? Should i be worried?

Btw while typing this question, the shortness of breath i felt before are gone... Im not sure why too.