Hey there, I do not have the answer for that one, but I have wondered that myself. My condition is very sporadic, so I at least for now do not have the chronic pain you speak of. However, it would make sense that someone with that sort of condition would lose a lot of sleep; and (according to my Dr) lack of sleep lessens your ability to fight pain - and pain does create stress. I believe it would also damage your immune system. I would think all of this combined would shorten ones lifespan considerably.

Just my unprofessional opinion - and I hope it's wrong.