TheBigCrunch

According to theory, the universe has been ever expanding since the Big Bang. Is the force from that initial event the only cause of the expansion of our universe? Also, if that happens to be true. Would the force of gravity slow the universe's expansion to a point where it stops all-together? since gravity affects matter in an infinite distance in all directions, would it not be true that the universe would begin to contract? Lastly, because gravity would be the only force affecting all the galaxies, would they over time condense into an infintesimally small and dense black hole, recreating the initial conditions for the Big Bang?