Question about Yu-Gi-Oh cards??

If a card's effect states that it's unaffected by spells, traps, and monster effects does that still apply when the monster is in your hand? For example, if you have a Obelisk and your opponent activates a card that makes you discard, is it still discarded or does it stay in your hand because of the effect? Does the effect still apply even if it's not on the field?