These are all dealing with direction and time, specifically, where someone is and where they were before. To go back (to) - To return to where one was. To get back - Can mean both "To obtain what one no longer has" and "To go (move,return) back to where one was (or used to be). To come back - To return from being somewhere else, but can be said from the perspective of the traveler(s) or the person/people from the original place who didn't leave.

These phrasal verbs have many meanings: 1. "to go back" To return from where I came. "I don't want to go back to the hospital." To remember an earlier time. "Sometimes, I go back to my childhood and remember simple joys." To repeat an earlier behavior. "Joe went back to smoking." To break a promise. "I can't believe that you went back on your promise." 2. to get back To return to where I came (more urgent). "I need to get back to the office." To retrieve something which I had before. "I need to get back the basketball that Ted borrowed." To move backward from something. "Get back, everyone! The dog is rabid!" To seek revenge on someone. "Tom got back at his teacher for giving him a detention, by telling the principal that she smoked at school." 3. to come back To return to where I was before (said by someone who is there). "Please come back and see us soon." To revive from death or near death. "Mr. Smith nearly died, but he came back." To experience again an earlier state or condition. "I hope that terrible cough doesn't come back." To return to fame. "The forgotten movie star made a come back with her newest film." To answer, to reply. "The President came back with a joke when the reporter tried to embarrass him." To give an insult when someone insults you first. "When the bully called the boy a nerd, the boy came back with, 'At least I passed the 8th grade!' "

Hi Luis, for more tips on phrasal verbs and English grammar go to; http://www.italki.com/knowledge/contribution-ENGLISH+GRAMMAR.htm Scroll down until you see the title Phrasal verbs.