Terrible Shin Splints, PLEASE HELP!?

I am a lacrosse player, and when we ALWAYS play on cement. And after about two minutes of running, I get terrible shooting pains that go up and down the in side of my shin, right before the muscle. And they hurt after, but not nearly as bad. In between running, while on the bench it hurts so much I can't stand. After the game, it only hurts when I walk. Please you have to help me. This is SEVERLY affecting my ability to play the game. I do stretch them before by putting them on theground with my thighs overtop, and laying back, if you get what I am saying. I've been doing this tretch for 10+ years, so it isn't this. Any advice would be greatly appreciated. THANKS