NW wrote:"I read that it was Theorized that pre BB there was a whole lot of antimatter."

R.L.- the term "pre-BB" has no meaning, current cosmological models have everything, matter and antimatter, being created at the big bang... actually that is incorrect- they condensed from the energy shortly after the big bang when the universe had cooled enough for them to exist.

NW:"Is this antimatter out there expanding into unknown space all around the Universe and is the cosmic background radiation the result of that antimatter reating with the sparse atomic particles it comes into contact with?"

R.L.- again "space around our universe" has no meaning... if there was perfect symmetry between matter and antimatter then there should be equal amounts of each today. However, and bear in mind it has been many years since I took particle physics, This symmetry has been found to be broken in some particle physics experiments (I think it was measured first in the decay of the Kaon??).