The back of my knee region on both knees is flaring up this past week. very painful when i bend them and try to get back up. this has never happened before. only rest helps and pain killers. they hurt even when i am sitting with my knees bent. like i

Please : Please have this evaluated. Sometimes arthritic changes can cause symptoms such as this. There is also a condition called "baker's cyst" that can cause swelling and pain behind the knees. The most important thing to be sure you don't have is a blood clot, which would cause pain, swelling, or cramping in the calf. If you have any of those symptoms you would have to have an ultrasound to evaluate your leg immediately. An ultrasound would also show a baker's cyst.