A body left in outer space, away from other bodies, will hardly experience any force other than weak gravitational force. Even at large distance, other celestial bodies, such as planets, stars, galaxies, etc. will exert their own gravitational influence over it. The body will experience some gravitational pull towards the center of the galaxy (depending on its distance from the galactic center) and will continue to rotate about the galactic center. It is also possible that the body has some velocity. If this velocity is more than the escape velocity of the galaxy, this body will escape from the galaxy. Remember all our satellites and rockets are provided with thrusters, to move them (for path correction) and keep them in orbit. Similarly, without an external or internal source to cause its motion, this body will also stay in some orbit, influenced by gravitational force (weak they maybe).
Hope this helps.