Asthma or something else?? 20 years old and i have breathing problems?

ok so i've been coughing for over 4 months now..used to smoke around 5-7 ciggarettes a day but i quit since i started coughing.....quit drinking too....it all started with bronchitis..i've been to the ER 4 times...for excessive coughing and shortness of breath..i recently got sent to a lung specialist..he diagnosed me with asthma..gave me advair 500/50 and albuterol pump..and prednisone because i think i had bronchial spasm...things got a littlle bit better..then i caught a cold and i had bronchitis again...got a z pack again and more prednisone...i still cant get a full breath of air..its like i have to sigh every couple of breaths or yawn to make my lungs feel full..the right side of my chest always feels heavy and it hurts at times..i dont know if its from the coughing or something else...went to the doctor again today..had a spirometer test done..he it twice .,..one regular..and one after giving me a puff of some inhaler...he said it was unusual i did better on the test without the inhaler..he gave me symbicort 160/4.5 and a prescription for a albuterol nebulizer.....i am really frustrated and depressed now..i feel like crying at times..i dont know whats wrong with me..i've had x rays done...i've had an ekg test done...blood tests...all normal...im literally sick of all this...i want to feel healthy again... i want to feel like the old me and not worry about my breath all the time...can someone please help me and tell me what this is???