in my view consciousness is not just about calculation
neurons only process information but there are other features of consciousness that don't just depend on calculation. Roger Penrose wrote two huge books arguing for quantum nature of consciousness based on this noncomputable side of consciousness, arguing mainly from the undecidable problems like the incompleteness theorems of Godel, even Ed witten recently claimed that science can never crack consciousness
Pain is not a thought, pain is some sort of a physical phenomena and of course it is a feature of consciousness, our awareness is not just a calculation in the brain, when we are aware of something or feel something we don't just calculate like a computer