Do I have Chronic Sinusitis? Problem since 2004

In late 2004 I had a pretty severe cough/cold. Ever since then, I've been somewhat congested regardless of the season and my throat feels enlarged. The doctors said repeatedly that it's post nasal drip, but the antibiotics and other solutions didn't work. It's not easy to sing or speak for a long period of time, and my nose is always clogged or runny. I also tend to produce phlegm and coughs are often productive. A CAT scan of my head showed little to no issues.
Any idea what this might be? What are possible treatments that will cure me once and for all?

[tomsant]

No idea about your age or other health problems. But the picture you suggests a chronic rhinitis which might be due to allergy. The throat / cough problems can be related to this.

Did you meet an ENT doctor?

Best rgds,

Thomas Antony