Sounds very much like my symptoms (intense knee pain/swelling and no rash), except that you don't mention low-grade fever and jaw pain (which I had). I was eventually on crutches and had an enormous amount of fluid (orange) removed from my knees. Cortisone helped a great deal.

For whatever reason they tested me for everything under the sun (rheumatoid arthritis, gout (!), etc) before testing for Lyme. I wish I knew then what I know now.

Know the symptoms, insist on the test.