Hello J Lem,
Thank you for using JA for your question.
Pain tolerance in general increases with age, is higher in males than females, and is slightly higher in caucasians versus blacks and asians
There is also something to consider called "pain sensitisation" as well. For example, the more an individual is exposed to pain, the less tolerance they have for pain. Therefore, it will create better pain control to give an individual with trauma adequate pain medication as early as possible. In other words, individuals will require higher doses of pain medication if pain medication is withheld until the pain is very severe.(http://en.wikipedia.org/wiki/Pain_tolerance). This does translates, into the idea, which is taught in courses to nurses, for example, that it is important to give pain medications to patients before the pain gets severe.
A study found that "Individuals high in pain-related fear groups had greater pain intensity ratings than those low in pain-related fear groups" (http://linkinghub.elsevier.com/retrieve/pii/S1526590004007485). This means, that individuals that self report fearfulness of the pain that a procedure could cause, were found to self report higher levels of pain to said procedure. This compares with those individuals who were less fearful about the same procedure and who were found to have less pain after the procedure. This translates into the idea, which is taught to nurses, that it is important to educate individuals as much as possible about upcoming procedures, in order to reduce fear, and thus reduce the chance of a painful outcome.
I hope this helps.
If you have comments or questions, please reply so that I can address them.