Constant chest congestion..

This past weekend I had a pretty bad cold/flu.  I was in bed with a fever, body aches, cough, etc.  These symptoms only really lasted for two days.  On Monday, my body was back to feeling fine, but the congestion was still there, which I expected.

Now three days later, though, the congestion is not letting up at all.  I don't really have any nasal congestion (unless I am coughing a lot and have to blow my nose), it's all in my chest.  I have been coughing literally nonstop for three days - not because I have that itchy feeling in my throat - because every time I exhale I feel all of this built up congestion in my chest and it feels awful.  I can't stop.  I assume that eventually I will have to cough this stuff up, but no matter how much I try, it doesn't even alleviate the congestion a little.

Other than this, I feel perfectly fine.  I don't have any other symptoms remaining, I'm not coughing up blood or anything alarming, I'm just not coughing up anything, really.  I've tried cough drops, hot tea, expectorants, decongestants, none of which helped even a little bit.  It's incredibly frustrating since I am going into work every day, but with the nonstop congestion I am always coughing and starting to lose my voice, making it difficult for me to do my work.

What is this a sign of and what can I do to alleviate this congestion?