Pain really is in your head. Although the physical sensation which causes the pain might take place at any part of your body, the actual sensation of pain takes place in your brain. And your brain is able to process that pain information in a number of different ways depending on the context. So, for example, if someone is involved in an accident, but they feel they have to take care of other people they may not even notice their own injuries until later. Their brain literally blocks the pain signals.
One way of doing this is to change the emotional context for the pain. For example if one person believes that pain is a sign that they are injured or unwell they are likely to experience that pain is suffering. Another person who believes that their pain is a signal that they are getting better is likely not to be bothered by that pain, or at least bothered a loss, even if the pain is of the same intensity.
The brain is also able to control pain more directly by generating a low-frequency brainwave signal in the part of the brain that corresponds to the area of the body where the sensation is. So for example if someone has pain in their foot, their brain can generate a low-frequency brain waves in the area of their brain that corresponds to that foot. A team of researchers from Brown University studied this phenomenon by asking subjects to focus on one part of the body while the researcher gently tapped another part while the subject was in a brain scanner. What the researchers found was that the brain tended to block sensation from the part of the body that was being tapped, but not paid attention to, by generating the low-frequency brain wave in the relevant area. However they also found was that this brainwave synchronized with a brainwave in the right inferior frontal cortex, part of the executive branch. Essentially the subjects had learned how to consciously block the sensations.
Obviously it is much easier to block a sensation when their is a light tap, then when it’s actual pain. But the principle is the same, by mindfully paying attention to one part of your body you can consciously block signals from other parts. This is why individuals to practice mindfulness may be better controlling pain than others.
For the hypnotist, this means that trance, which after all involves focused attention, is so effective at dealing with pain. By taking a client into trance and focusing their attention on one stimulus, for example the feeling in their finger, they can effectively block sensations from other parts of the body. This can lead to the hypnotic phenomena of ‘glove anesthesia.