Hi Stewart,
Welcome to NT. Fear and pain are both terrible to endure. And I know its not easy to let go of the fear and the fear probably even exaccerbates those angry nerves.
I once worked with a hypnotherapist to help me conquer some of my fear. Now when I feel my self holding and tensing I talk myself through it before it gets bad. Not a cure but it helps.
Please let us know if you need anything at all.