I did a pain survey of members of this forum, and our sister forum, a few years ago. I asked people to score a number of things based on their 1-10 cluster headache pain scale.
I then pulled in all the results and averaged them, and the results are listed below.
But like BoF said, pain is subjective. A couple examples:
Kidney Stones ranged from 5 to 9, with 7 being the average. Personally, I'd the kidney stones I once had at a 5 compared to a cluster attack.
Broken bone ranged from 1 to 9, with 5 being the average.