It is not easy to tell if an infection is viral or bacterial. Many times, they will both give you the symptoms you have described. Acute bacterial infections are more likely to cause a fever. Chronic sinusitis is not. Some viral infections have a fever, others do not. Viral infections are far more common in the winter, usually go away in 3 to 7 days and are mostly an annoyance. Bacterial infections may not get better without antibiotics and make you feel really badly. There are medications that loosen the congestion and make it easier to cough up. They are medications that contain guiafenesin.
If these symptoms are persisting and not improving, you should see your physician.
Here is some information from the American Lung Association regarding pneumonia.
http://hcd2.bupa.co.uk/fact_sheets/html/Pneumonia.html
http://health.allrefer.com/health/pneumonia-symptoms.html
http://www.emedicinehealth.com/articles/17666-3.asp
These may also help. The emedicine writeups are generally quite good.
Chills and fever are never good. Sudden onset can indicate pneumonia. If you haven't called your doctor yet, you really should call ASAP, especially if you have any type of chronic lung condition.