Hard to breathe, chest xray "clear" but never heard back from dr, advair helped, still need to take big inhales to breathe. no smoking. lung cancer?

Highly unlikely: At your age that's highly unlikely, but bronchitis and/or asthma could definitely be playing a role. The fact that Advair helped is a big clue, as that medication reduces airway swelling, mucous production, and helps to relax muscles that can tighten around the airways as well. You may benefit from continued Advair and/or prednisone, and I'd talk to your MD about both! Hope this helps.

Call doc: The good news- likely nothing serious. Cancer extremely unlikely. The bad news- you are still suffering. It appears that you likely have asthma. Do note that Advair takes 2-3 weeks to provide optimal benefits. You should call your doctor. If the answer does not satisfy you consider consulting an allergist.

Dyspnea: Given your age anxiety is likely a component of your symptoms,it sounds as though you need to connect better with your Dr as he/she presumably saw fit to prescribe a two drug inhaler and order a chest xray in a young person,Please follow up with him/her for resolution

Unlikely,: IDK how long you have been on advair, but usually takes a few days to get the advair medicine to all the 300 million air sacs (alveoli), that need to get treated. Lung Cancer would be very unusual in a 20 year old. If it has been over three days, then another visit might be helpful, with the addition of PFTs (pulmonary functional testing) of the lungs.