W.W.
Hi G.,
My son had the identical thing and it lasted for about 14 months. The one and only, absolutely thing that worked for us was to put on his favorite Wiggles dvd. Even with reflux pain he would stop his crying dead in it's tracks. I have no idea why this worked, but it did it every time. Try it and see if it helps. Help comes in the strangest forms sometimes.
Another thing that may help is to record on paper everything that she ate or did on that day, especially immediately before, of the attack so that you can see if there is a connection.
Start her on some good probiotics too.
Good luck.