Armor Mitigates the Physical Damage

   • Armor mitigates the physical damage you take at all times, so, while I'm not exactly sure how to answer your question... The amount of armor you have will still affect the damage you take while Power Word: Shielded.
   • As in, if you have no mitigation and something hits you for 1265(assuming no bonus healing or the Improved Power Word: Shield talent) the shield will break. If you have 10% mitigation from armor(again, no bonus healing, etc.) something that would hit you for 1265 with no mitigation will only hit you for 1138.5, so your shield will only take 1138.5 damage and will have that extra 126.5 left to absorb.
   • Pain Suppression reduces the damage you take by 40%, being an activated ability it comes in to play after mitigation and Spell Warding. If something was to hit you for 1000, let's say you had 10% mitigation again, that thing would only hit you for 900; with Pain Suppression activated you'd take that 900 damage and further reduce it by 40%, meaning you'd take 540 damage instead of 900.
   • Same goes for Spell Warding. If you were to take 1000 damage from a spell, Spell Warding reduces that damage to 900, then Pain Suppression further reduces it to 540 damage.