What could cause these lung symprtpms?i take advair and albuterol either help.?

shortness of breathe,feeling like not enough airs not getting in.pressure and pain.i have this 24/7 not one moment from when i wake up till i sleep.i dont' have allergies,i don't i have asthma.i was told i have bronchitis but no mucus or cough.i don't think i have cancer.im 21 and smoked for 5yrs.im currently stoping smoking by replacing smokeless tabacco.i once had pluericy im not sure if it disapeared ever.x-rays show my lung is fine.my doctor can no longer help me so in a month i see a lung doctor.i wont be able to get a c-scan cause its very expensive.i was scheduled for one then i found out they want $500.00 up front.so i started going to e.r.s they're no help either.so now i suffer daily it cause me to loose my job also.ive done research it could be multiply things so i got tired of worrying my self with all the things it could be.i get so mad cause i can't take deep breathes.any opinion would nice.now all i can do is pray and wait hopefully i don't stop breathing and die.