At times i have a hard time breathing. it feels llike the only time i get a full breath of air is when i yawn or sit up straight. could it be anallery?

SOB: What is anallery. Do you mean an allergy? First see the doc so he can check your lungs. You may need a pft or chest x-ray. If your allergic history is positive it may cause lung problems. If everything checks out ok, consider a manipulative treatment.

Could: It be an allergy, maybe, could something be obstructing your airway or a form of asthma are other possibilities. Also inflammation of the lung lining, so go have that checked with your doctor.