what kept me away from work this week...

Tracheitis – Inflammation of the Trachea (windpipe).

Here are some info I gathered about Tracheitis:

Tracheitis is a bacterial infection of the trachea usually caused by viruses responsible for Colds, Influenza, Laryngitis and Bronchitis whereas the most common cause is Staphylococcus aureus.

Symptoms:
Causes a sore, burning sensation as air is taken into the lungs;
Intercostal retractions (the muscles between the ribs pull in as one attempts to breathe);
The trachea feels as if there is a raw, sore streak down it, with the mucus (tenacious, sticky phlegm) too far down to be coughed up.

Frequently, Tracheitis follows a recent viral upper respiratory infection (which I had about 3 weeks ago – influenza).