IMHO, he does have this power and this is how to resolve the seeming illogic of not being more pain sensitive. Pain is the perception of damage to body tissues. If the sensation is not accompanied by actual tissue damage then his super-perception of pain isn't triggered. This must be so else his heightened vision and hearing would similarly make him more vulnerable to pain attacks through those senses, yet things like nukes don't blind or deafen him nor staring into the sun blinds him either. Clearly, he's invulnerable to those forces so no tissue damage and thus no pain sensation results. The same would apply to his super-touch and pain sensations there.
I agree completely with this as I've always thought the same. It could also explain he PreC ability to detect electrical discharges as cited on this very site.
on at least one occasion, his own body went super-elastic as opposed to being pulled apart (he was being sucked through a space warp and this body was being stretched out like the Elongated Man's)
When did this happen?