"Suffering/pain is a protective survival mechanism produced in the brain in response to tissue injury in order to prompt an organism to act/modify its behaviour."
This is exactly the same as saying 'all suffering is for a purpose' - which is precisely the position that Stephen Fry et al attribute - wrongly, actually - to Christianity and other religions. And, of course, it only really works as an explanation of natural causes of suffering.
"But if some sentient being created the world and chose to create, or even just allow to exist, diseases that cause pain, distress and death; then they are definitely malevolent. And the suffering we endure was created by them not by our minds."
Once more, this argument only works in relation to natural causes of suffering. And, as I pointed out in my previous post, this is a classic anthropocentric position. A God who loves all his creation, all the life-forms that have evolved through natural selection, and to whom they are all good, will love the virus and the mosquito as much as the human being.
But how does Outwith's evolutionary explanation work in relation to suffering caused by humans on other humans (and, indeed, on non-human life forms)? What is the evolutionary advantage of torture or rape, of the myriad forms of cruelty, exploitation and unkindness on which human beings have expended so much ingenuity and energy? Can God really be credited with each act of violence (be it physical or emotional) committed by one human being, of her or his own free will, on another?