If 10)...Bg5 (one move earlier) you have the pin.
But if 11) Ne2 Bg5, 12) f4 your pin is gone. White loses a pawn but your pin is no more.
So you missed the winning move, but your opponent made three dumb moves in a row (starting with 0-0-0), and he basically saved the pin for you, by playing 11) Nb5.
Sorry.
In this game, you will see me take advantage of a positional weakness in my opponent, pinning his queen against his king after trading my knight for his (thus removing my only obstacle). Check it out!
Link: http://www.chess.com/echess/game.html?id=51927455