When you are anxious and/or in pain your body becomes tense, this makes the pain worse, you then become fearful and the cycle continues. When you are in a relaxed state you feel safe and calm, you let go of tension in your muscles, you relax your nervous system and this helps it to become less reactive to pain. Hypnosis is used to reduce your stress and anxiety and install positive thought patterns which can make a difference to your perception of pain.
Distraction is also a way to help you manage your pain and often in hypnotherapy we use visualisation to give your mind something else to think about, you use all your senses in your imagination to see, hear, smell, taste and feel somewhere pleasant and relaxing for you.