Only the owner of “Fear from the Dark” can use its effect, because it has to be sent from your hand to your Graveyard.
When you discard “Fear from the Dark” with “Painful Choice”, “Fear from the Dark”’s effect does not activate because it was your own card effect that caused it.
If “Fear from the Dark” is sent to the Graveyard during a card effect’s resolution, or during a chain, activate “Fear from the Dark”’s effect after the current effect or chain has resolved.
If “Fear from the Dark” is sent to the Graveyard by “Last Turn”’s effect, “Fear from the Dark” is Special Summoned to the field before the attack of “Last Turn” happens.