My life coach, Iben, once told me that some people with chronic pain stay in that state to get nurturing and attention. I bristled at this comment because no one wants a pain condition to be discounted as manipulation. One has to be very careful in making these connections. The pain is real and usually many factors contribute to it.
I was only able to consider this possibility when she clarified that this is often a subconscious reaction rather than a conscious choice. It helped me move from judgement to compassion when I considered that these people are trying to fill a core void however they can. On a subconscious level, they are hurting themselves physically to avoid dying emotionally.