Oh yes, i've had this too.
Just went to see my doctor last week. My doctor said i need to continue taking Mucinex to break up the thick chunky phlem. The Mucinex is helping breaking up the phlem and i also sleep with a humidifier on due to the air so dry. I also use the NasaFlo Netti pot to clear the nasal and this helps alot.
Hope you get better soon. I've had mine for 2 weeks and the phlem is better using the above.
BeHappy2