[limey]

Maybe depression groups might offer what you're looking for? I am not in your position nor have I suffered from depression, but I am close to someone who does, and what you say reminds me of what he describes and acts out I am not saying you are suffering from depression, but the mental pain they feel may be closer to the physical pain you feel in its effects.
Or you could try disease-specific groups where pain is a major factor of the disease? I'm sure that the dwellars here will let you spill as much as you want when you want here, too ...