What Causes Extreme Pain And Swelling In Knee?

I have a synovial cyst at L3-L4 to the right of the spine. When I went to the hospital 2 weeks ago with severe right leg pain, after much testing the cyst was discovered. I have not been able to have any treatment as of yet because at the same time I developed chest pains and it was discovered I needed a stint for a blockage. Until I come off the Plavix I am on pain management. My question is yesterday I over worked my leg and back. Today I am in extreme pain and my right knee is swollen. I have had to take my breakthru medicines. Is this swelling and pain normal when over using my back?