Leg stretching workout pain?

I was stretching my legs to get a full split and I started feeling pain in my right leg below the knee, all aroung. I'm 5'8'' tall and I was stretching 6 foot. I was advancing until I started to feel the pain. This question is for those who practice martial arts like karate, tae kwon do, sipalki or kung fu. I'm looking for the answer of someone with experience and they know what I'm talking about. Those who don't know please don't answer saying go to the doctor. I haven't done any stretching for a week. Anybody knows? Thank you.