I think everyone has a different pain tolerance much of it psychological. When you grow up you see people in pain and their reaction to it. Perhaps their mother had a headache with a low pain tolerance and exhibited symptoms of someone with a brain tumor. So when the child gets older they act out the same way. My father could be half dead and never complain. I have a good tolerance for pain. I just recently got over a triple by-pass and a load of smaller but painful surgeries, yes I do complain but just try to go with the flow. I remember a thing I learned when young, I'm not sure where but the quote is "and this too shall pass away." So I know no matter how bad things are, and how much pain I'm in, there will come a time when that pain will be gone. One last thought, You'll never experience more pain than you can handle, if and when you get to that intolerable level, you will pass out and no longer experience the pain, either that or kick the bucket.
Brain damage,nerve damage,thick skin,use to it.or disease or illness may cause a person not to feel pain also in some cases the body shuts off the pain in order to survive in a traumatic injury. I snapped all the bones loose in my right foot and at first I felt nothing but I could not figure out why my foot would not work then the pain came a few minutes later so when the medic arrived they gave me morphine .I did not even realize my foot had basically folded into/upon itself until later when the surgeon told me what they were going to have to do in order to fix it.the funny part is I had to ask the medic to straighten my leg up so my foot would be in the right position instead of laying horizontal to the right .in other words my leg and foot was turned in a way that I could not normally turn it(was not natural for the human body).it kind of freaked me out.but I did not feel a thing after the morphine was in. Woooo hoooo! Thank God for morphine.
The reasons Jackyl and Nomad gave are pretty good. Pain is essentially just an electric current running from the source to your brain, and then off to other parts of the body. When we experience pain, almost instantly pain-reducing hormones are triggered by the brain to be released. A person might have a higher pain threshold for this reason. It is also something that you can train your body to ignore (much like the cold, hunger, etc.). Pain is much like a drug, in that you can get addicted to it and also build up a tolerance for it.
Everyone is different.
There is some research which suggest that some people have a naturally higher tolerance for pain than others based on physiological differences.
Pain is all in the mind. I stopped feeling pain since I was 8 , ive done so much martial arts and training that pain is not even pain , remember pain is in the mind, its not physical its mental so if you belive something hurts then it will and if you make youreself think you can't feel anything , you wont! Simples!
Because everyone has either thick skin or thin skin. So the ones with the thick skin can tolerate pain while the sensitive person can not tolerate the pain. It all depends on the person.