I woke up in the middle of the night and stretched my legs while lying in bed. Big mistake, apparently. I don't know what I did, but it felt like my calf muscle was tearing away from the bone, ouch! I leap out of bed as fast as I could to try and relieve the pain. I did different stretches and it finally went away. When I stretch it now, it still feels a little sore. Weird, right?