Why do your lungs till have some extra phlem a few weeks after a cold is over?

My cold ended almost 2 weeks ago and I’ve still got some excess phlem. Not gobs, but more than usual esp in the evening. It always goes this way ever time I have a cold (ie cold over then 2-3+ weeks for excess phelm to clear out). It’ll take almost a month or so for my lungs to be competely clear. Why so long? The cold is gone.

I don’t know, but I know you are not alone.