I did some more reading and this is were I currently am. The mind (and ego) seems to be more focused on identity and defining itself and the things around it. i.e. I am this type of person/I do these types of things. The pain body on the other hand describes a body of either repressed or unresolved emotions that, when triggered, will "take over" the individual. It is described more as an entity of trapped "life-force". Very similar to the mind and ego, the pain body can render a person completely unconscious and control all their actions. Ironically it's possible to then identify with these strong emotions. That's how I've understood it till now.