Oh, on the evolution topic...
No! Evolution doesn't work that way. Having two functional arms is more advantageous than having 3 arms with one that is functional and the other two that have screwed up nerve pathing (which is my assumption for why either arm hurts when it is touched and could explain a lot of the disfunctionality). And changes like that don't occur in nature. You don't see any mammal species with extra limbs. Also, because of the nature of evolution, it doesn't really apply to humans any more. Strength and intellect grant you barely any advantage in extending your offspring, and the ability to do more because you have a third arm certainly wouldn't be an advantage for that.