You can find 7 Hidden Chambers in God of War. All Hidden Chamber Locations require the Magic Chisel to open. This item is story related and can be found by following the main story to chapter 7: The Magic Chisel.
Take the boat to the new region Tamur’s Corpse and fight your way through the icy mountains. After a boss fight at the end, you can carve the chisel out of the wall. The chisel remains in your inventory from now on and can be used at the hidden chamber doors that have been locked until now.
more God of War
God of War | How to find ANCHOR OF FOG (Best Chest Loot in Nilfheim / Unlocking Epic Gear)
Farming Mist Echoes / Nilfheim Chest Locations in God of War (Secret Areas + Opening Nornir Chests)
God of War | Unique Axe Pommel Puzzle Unlock (Forbidden Grip of the Ages / Best Gear God of War
Fully UPGRADE Leviathan Axe in God of War (How to find Chilling Mists of Nilfheim / Frozen Flame)
Fully UPGRADE Blades of Chaos in God of War (How to find Raging Inferno of Muspelheim + Chaos Flame)
Crafting EPIC Armor / How to get Smouldering Ember + Crest of Flame in God of War