If you have ever been taken to hospital, think back to when you saw the triage nurse. You would have been asked a question, “How much pain are you in, on a scale of 1 to 10?” The first time this happens to someone, they will nearly always aim high. Broken bone? Headache? Burn? They will all be reported as 8,9 or even 10. But then something worse happens. Perhaps that rates at 10. But that means that the previous pain can’t have been 10, so it must be re-evaluated and bumped down to a lower number.
Tolerance of pain varies completely from person to person though. Some people can shrug off pain that has others clutching at the affected area and swearing or shouting about how much pain they are in. I would imagine that they rate the same pain as somewhat lower on the scale than others.
On my own personal pain scale, my neuropathic pain is sitting somewhere around 3 or 4 this morning (With the aid of quite a lot of painkillers) but without painkillers can often by around 8 or 9. I would rate my migraines, which are very debilitating, as about 7, although I once would have said they were 10. The migraines had to be bumped down the list a bit because the perianal abscess that I had last year definitely has to rate at 9 or 10 and was the most pain I have ever endured. I think there must be worse pain than I have experienced, for example the extensive damage inflicted by a road accident must surely be more painful than my abscess was.
This presents a problem for people that experience lots of pain. When going into hospital and being asked to rate the pain, giving 4 as an answer gets you dumped to the back of the queue. A pain level of 4 is not a problem. And yet, that 4 may well equal the pain of the next person to answer the question, who having no further experience of pain, will answer 10.
There’s no solution to this problem that I can see. Pain is entirely subjective and cannot currently be measured, and if it were to be measured, the sensitivity and reaction to pain in the subject would also need to be measured in order to rank the severity of each case.
Still, as a bit of fun to lighten up a horrible subject, go take a look at the pain scale over at Hyperbole and a Half.