1:when tu reach the 2nd section of the cave head right pick up the shotgun turn left & fight him
use the shotgun o a grenade when he is covered in bees.

2:when fighting the fear of course tu can't see him
when tu are in the factory where tu get too sokolov(not during vartouis mission)in the room where sokolov was held there is a locker open it & there tu will find the terminal goggles use it to see the fear even when he is in camo.

3:after tu defeat the pain tu walk a river when tu are in the end of the river turn left.there will be two soldiers take them out get on the platform...