About breathing and mucus on the lungs?

I used to smoke very heavy,up to 2 packs a day.I quit smoking for 6 months now on Champix....I am clean but hoping to cough out any toxins and tar etc. that is in my lunges...Nothing coming up,but they said you will lose it in your urine and stool as well over time...(not sure if that's true)but...recently my lungs feel very flemmy..Hardly anything comes up on a cough and if anything does,it's clear...I am having alot of trouble taking air in though and every time I swallow there's a small amount of mucus going down.I even wake up from my sleep needing air on occasion,then I rush out to the air conditioner and take cold air in and that seems to help alot.Does this sound like a temporary infection possibly,a cold possibly or my lungs just beaking down all the bad stuff from when I smoked,or something more serious?Thanks