Hello I just read this post. I thought i'd chime in here for a brief moment. I've had several of these daggum buggers in the past, and im certain i'll have more to come. I get them alot either at night while I lay in bed and stretch, or the most recent one was on the tredmill running. It was the weirdest thing...I was running and I heard a pop! I immedietly fell off the tredmill in teh middle of the gym.. talk about embarrassing.. I coudl not stand up or walk..I had 3 people help me to the dressing room. It was crazy.. I never went to the doctor for it, I just wrapped it up when i got home stayed off of it and walked on crutches for about 2 weeks.. It eventually healed up.. But just last week the same leg/calf area as i was sitting on the couch just after a light cardi workout my calf locked up and it was excrutiating... I've had these for many years... i have no idea what causes them or how to get rid of them other than jump up and down and scream like a little girl... LOL that usually helps...
good luck, if you find out anything please let me know