knee pain--bursitis??

After a week of pain in my left knee, I went to my doctor who diagnosed bursitis. He recommened moist heat and ibuprofen. The strange thing is, while I have discomfort sometimes during the day, it is about 1:30am when I awake in intense pain around my kneecap. The skin is painful to the touch and when I get up and walk, the pain is usually relieved. This has been going on for about 2 weeks now. Could this be a nerve problem?