Appending 'Schmain' to 'Pain' indicates complete nonchalance on the behalf of the utterer with regard to the promised, expected or forthcoming pain.

The idea being expressed is that Pain will affect him no more than Schmain would. There is no such thing as Schmain.

Someone who is possessed by clout chasing. The original human is now gone and a demonic entity that feeds on clout is all that is left. An empty shell with no control of their actions, forced to blindly react to situations they think will bring them attention.