Trudy - email@example.com
After suffering for 3 years - and consulting with several so-called specialists without success, out of frustration I found my own cure. At least it helps a little.
I found a small, very soft sponge ball - the size of a ping-pong ball. Placed it between the buttocks, just below the tailbone. Although this is not medically correct I am now able to sit and lay down in reasonable comfort.
I also have to adjust my "ball" up and down a few millimetres depending on how, where and on what I am sitting. Very lady like!
Note from Jon Miles: I have not heard before of anyone trying this method. If you do try it, please let me know how you get on. If you can't find a soft sponge ball as described, you could always cut a small block of soft foam down to the size of a ping-pong ball (40 mm, about one and a half inches) with scissors.