Don't be too quick to label your shoulder pain as bursitis, especially if your condition doesn't improve after a few days of rest. There are many conditions for which shoulder pain is a symptom, but absolutely none for which pain and swelling should be ignored.
A physical examination by an expert, usually followed by X-rays, is the first step in proper treatment. See a doctor if your shoulder pain is interfering with your everyday activities or your sleep. The same can go for other joints, too. While bursitis may be the most likely diagnosis, it's not the only diagnosis.