On Saturday I Fell After Taking A Shower. I Was

On saturday I fell after taking a shower. I was shaken, had mobility, and not in pain. Waking on sunday I was in great pain and unable to walk unless shuffling with all weight on left leg. Right leg was agony with any movement including trying to rise from a chair. Saw doctor who said muscle pulled and advised pain killers, saying it would gradually heal itself in maybe a wekk or two. On monday the pain had gone and I could walk without agony. I have had no further pain. Q: Was this really a pulled or torn muscle ? and how was my recovery so rapid ?