What is chronic bronchitis and what effects does it have 2 a 13yr old teen?

my doc said i had chronic bronchitis after my flem built up in my lungs and i had problems with breathing still. I go to the respiratory building a lot in th hospital i hav 2 do respiratory checks. All of this happened after i got a cold and after that i'm sure, i got diagnosed with hyperthyroid. I'm the only sick 1 in my family my lil bro all healthy. So can any1 tell me the effects of it? thnx !!! ^.^