Would pool strike and elemental touch stack?
Pool Strike (Su): "The magus can expend 1 point from his arcane pool as a standard action to charge his free hand with energy. He can make a melee touch attack with that hand as a free action as part of activating this ability. If the touch attack hits, it releases the charge and deals 2d6 points of energy damage (acid, cold, electricity, or fire, chosen when he spends the arcane pool point to activate this ability). He can use this ability with the spellstrike class feature. If he misses with this attack, he can hold the charge for up to 1 minute before it dissipates."
Elemental Touch: "You gain a melee touch attack causing 1d6 points of damage of that energy type, along with a special effect described below. You also deal energy damage and the related special effect when you attack with your hands using an unarmed strike, a single claw, or a single slam attack. This bonus damage can never apply to multiple weapons."
When touching: maybe. It depends on if the "touch attack" granted by the abilities is a discrete thing, or if it just counts as anything you touch (like a held charge). If the latter, they would stack. If the former, then you would choose which touch attack you're using at the time.
When using unarmed strike or a claw or a slam: If those are considered weapons, then yes. A successful hit would deal weapon damage, elemental touch, and pool strike via Spellstrike. You may find GMs who don't consider unarmed strikes to be weapons, so it may only work with natural weapons.
I would caution you to cast Elemental Touch first, as Pool Strike says you can hold the charge, which should mean you follow the rules for held charges, meaning the effect will dissipate if you cast a spell. (You don't have to worry about dissipating Elemental Touch, since it's not a touch spell, even if Pool Strike was not supernatural)
Ask your GM first. If this is for PFS, I would certainly avoid building a character around it, and expect it to not go over well at many tables. People get cranky at magi using their standard abilities, cheesing out an elemental touched pool striking shocking grasp may result in rulebooks being used as improvised weapons.