I'm sure many of you will have read "Spoon Theory" (link at the top right hand corner of my blog)
Well, to keep up the theme of cutlery, I thought I'd offer you Fork Theory.
Trying to explain what "Pain" means is useless. Everyone feels pain differently and we're programmed to forget any pain we have experienced. If you really want to go the whole 9 yards and understand what living with pain is like, give Fork Theory a go. Nurses might find it especially useful.
Sit in a quiet room, preferably alone and get comfortable. Take a fork, and press the tines it into the skin of your thigh. Use enough pressure for it to hurt, but obviously not enough to cause any actual damage. (Please remember that bit or I'll be sued from Surrey to Skye ;) )
This experiment works even better if you do it in the middle of the night. Whatever happens over the next hour, you must not stop pushing that fork into your leg. You can't relieve the pressure you apply and you can't get up to do anything. You can't get a drink or call out for anyone to help you, because they won't hear you.
Time the hour exactly. As it passes, notice if the pain seems to get better or worse. Does time speed up or slow down? Are you counting the seconds as they pass? Can you concentrate on reading a book? Could you do a full day at work?
This is the closest I can get to explaining how pain overrides anything else. Sadly if it had been real life, you wouldn't have known when it was going to end, or indeed if it would end at all.