Not nice at all; broken collar bones certainly are painful. Hope you have a quick recovery. Hows your bike? Hopefully that didn't suffer too much damage.
When I broke my collar bone a few years ago I got a prescription for Codeine to cope with the pain. The side effects of the codeine (Headaches/Constipation/etc.) was so unpleasant I stopped taking it; I personally found the side effects to be wore than the pain.