Pain is a hard thing to describe. I usually say that when you get the onset of a migraine, you worry that you are going to die. As it progresses, you hope that you are going to die.
On the positive side, nothing beats the feeling of waking up and realising that the pain is gone. You're scared to move at first, in case it starts up again but finally you realise you are OK, pain free and appreciative of the world in ways the non migraine sufferer will never know.