That's the message you see when you are the one that has offered the draw. It is pending because your opponent has not accepted or declined it, yet.
It is possible that you accidentally clicked on the 'offer draw' button, perhaps when you wanted to use the analysis board. I know I've done it before.
I am a quite new to this site, and have just been offered a draw, but I don't see where to click to accept it. All it says beside the board is "You have a pending draw offer." Help!