I guess it is possible you strained it. I would but some heat on it and rest a day or two.Take some asprin. If the pain is worse or travels go see your Dr. Not to scare you but blood clots can start in the calf. But if messaging it and adding heat help I would say it's muscle. Do you know if you did anything to it that you remember? Doesn't sound like you remember though. How big is your calf, I bet it's not as big as you think. Here I will measure mine (measuring calf) mine is 14 inches. Now that seems big to me.
Blessed are the flexible, for they shall not be bent out of shape.
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