Is it theoretically possible to objectively quantify pain?

This thread got me wondering whether pain that different than many emotional complaints such as depression, anxiety or malaise? Or complaints such as fatigue. A significant majority of people may react to an “injury” in a certain manner, but a minority of folk maintain that they are profoundly impaired by their experience.

So perhaps, it might be possible to devise VERY general guides as to the expected reaction (pain or emotional) to certain injuries, while acknowledging some folk may have a greater or lesser reaction. For those folk who are towards the extreme, it might be valid to question the degree to which some other factor is contributing to their perception/claims. I also imagine that, as you approach those extremes, it might be more challenging to try to factor out physical versus mental/emotional bases for their descriptions.

You can measure a body weight and this will be more accurate than whatever the patient thinks it is. But, in the short term, you cannot do anything about that weight - nor do you have to.

There is an expectation that doctors treat pain. This is a reasonable expectation, and quantifying it, even approximately, provides a way of seeing if the intervention helped. There are better ways, such as patient controlled anaesthesia, which are reserved for certain in-hospital situations because they require a lot of expertise and equipment.

Pain is certainly affected by mood and malaise. This increases personal variability. But no doctor would have trouble saying an impacted kidney stone can be more painful than a dislocated shoulder or ranking, in general, many similar conditions. Like many statistics or anecdotes, the results apply to a big group - but not to you, an individual.