Is it a sin to retaliate? What if someone hit or shove you are you allowed to hit back?

This is a complicated issue. It depends on which religion, different things are sins in different ones. If you're jewish, I think you're fine. Christians have jesus saying love your neighbor and turn the other cheek so I don't think you can. But on the other hand jesus also cursed and insulted his enemies, and attacked people with a whip of cords, so if one was to act like jesus I think you can do whatever you want. However often this god can do things humans aren't allowed to do, so I don't know.