I have (recently diagnosed) eczema, my house (moving in October) is old and has some mold that causes me to break out in a terriblely itchy rash. If I leave my house for a few days it goes away.
Is my house causing my rash? No. Is the mold causing my rash? No, indirectly it is. It is my eczema that causes the rash, the mold triggers it, the house just happens to be where the mold is.
E-cigs, just like everything else, work just like that. They may be the carrier (as my house is) or the trigger (as the mold is) without actually being the cause.
Years of smoking causes a lot of damage, and keeps your lungs pretty damaged. As they start to repair and reactivate (due to lack of inhaling smoke) many things can happen. Most of us go through a period of coughing and expelling large amounts of phlegm. But these are the same symptoms of quitting smoking in any manner.