Might be sinus issue, When they drain I too get a lot of phlem and it seems to get stuck & is difficult to swallow. Try an ENT
Also I would try to quit smoking & I know it is very hard I too am trying to quit. I'm going for accupuncture to quit.
Good Luck
With the phlem do you experience trouble swallowing? I am a non smoker and I have this problem, its due to my thyroid being slightly larger than it should be. You may want to have it checked out. I have the phlem that feels like it is stuck in my throat, and once I make myself cough it up it looks like a ball of rubber cement. (sorry if I grossed anyone out) It varies in color, from like an opaque color to sometimes a greenish, but like I mentioned its a ball and sort of slimy but yet firm.
i didn't mean to be preachy there but it seems like your body is telling you what it needs and screaming for you to listen.
I would experiment and I would purchase some saline drops at your local Walgreens and use those.