What Causes Knee Pain While Treating Bronchitis?

I recently was on a course of antibiotics for Bronchitis, the second time in 4 months. I had an interesting and encouraging reaction. I have suffered from a lot of knee pain, and ankle pan, so much that stairs have become difficult for me. During the 10 days that I was taking the antibiotic my knees became less tight and the pain virtually disappeared and I found myself being able to run up stairs. Now, a week after ending the antibiotics, the pain is back. I ve filled in my doctor on all this, using the patient portal but haven t received his response yet. Still, I m interested in what you might think about this. It was a pleasant surprise to me, and if my problem is something that can be cured my quality of life would improve dramatically.