if a character has a natural attack like claws or bite (eg. sorcerer dragon disciple) and they cast and store a touch attack charge, do they have to use a touch attack to use it? or can they use the touch spell on a normal attack with the claw or bite or other natural attack as it is still technically touching?
Charges of a touch spell will discharge on successful natural attacks and unarmed strikes. Just remember that now you're targeting normal AC instead of touch AC.
Under Holding the Charge:
Alternatively, you may make a normal unarmed attack (or an attack with a natural weapon) while holding a charge. In this case, you aren't considered armed and you provoke attacks of opportunity as normal for the attack. If your unarmed attack or natural weapon attack normally doesn't provoke attacks of opportunity, neither does this attack. If the attack hits, you deal normal damage for your unarmed attack or natural weapon and the spell discharges. If the attack misses, you are still holding the charge.