I am having sharp pain in the back of my knee. Swelling started soon after the pain. The pain radiates to upper parts of my calf and lower parts of my thigh. There have not been any recent injuries though we have tried using R.I.C.E. All movement causes the pain to worsen. I have taken various pain relievers over the past few days and nothing provides relief. I'm not on any medication other than recently starting birth control.