Refers to literal movement, often repetitive, as seen in objects or people. The fan's blades spun back and forth, cooling the room.
Pro Tip 2/3
Indecision
Metaphorically describes someone's inability to decide, as if their thoughts are moving in different directions. She paced back and forth, unable to choose a dress for the party.
Pro Tip 3/3
Repeated Action
Used to express actions that are done several times or continuously. The guard walked back and forth in front of the door.