I had arthoscopic knee surgery 3 weeks ago. I am now experiencing calf pain. After sitting for a while, I will get up and not be able to put pressure on the leg at all. When I flex my toes upwards I also get a pain. After I walk on it for a while, it seems to loosen up. I thought it was maybe a pulled muscle from not being able to walk properly. Doctor sent me for a blood clot test which was negative. So, I am wondering what else could it be?