i had surgery on my foot 7-3-16 and then in my sleep three nights later I stretched and felt a pop behind my knee and some pain in my calf. Two days later i had intense pain in the back of my ankle and calf muscle, ER dr said torn muscle. Last night i had sudden intense pain behind the knee that radiated up into the thigh which was bearable and down into the calf which was totally unbearable. the pain lasted for about 5 minutes then subsided and about 20-30 minutes later it hit again, exact same thing lasting 5+ minutes. No further pain the rest of the night and so far today all is well.