Wait a day or so. If the pain doesn't go away or gets worse, go back or go to the hospital... Because you could have an abcess forming.... And left unchecked, can be one of the most painful ordeals one can go through (many women say tooth abcesses are worse than childbirth)
Is the pain more like an ache or sore? Or is it throbbing/feels like there is a lot of pressure?
It's a root pain. Like when the dentist drilled down to the root and it's ongoing. Because I didn't have a filling for the last years and when I had one it never hurt - I don't know now if this should be normal or not.
BTW: I don't think it can be an abcess. How can such a thing develop in 9 hours when there was non before 
Do you have to go back to the dentist in a week or so for stage two? Because I had an experience that sounds a lot like yours (drilling down to the root, putting in a temporary filling, returning the next week to 'clean the root' and put in a definitive filling) and that certainly did hurt a couple of days, which is why my dentist gave me a pain-killer.
