nasal problem

Hi - can anyone help ? Over the course of the winter I have suffered a few bad head colds which have left me with thick,congealed catarrh which feels as if it is stuck at the back of my nose or even further back.Based on the consistency and colour of it(brown), it would suggest that it has been there for sometime.
I have tried steam inhalation, saline nasal rinsing, oil pulling , but nothing seems to be able to shift it.
Has anyone else suffered from this and managed to solve this problem successfully? You're help would be much appreciated.