A Pain Psychic gets Live On, which is Lay on Hands at your psychic level -3. It explicitly stacks with lay on hands abilities gained from other sources.
A VMC Paladin gains the ability to lay on hands a number of times per day equal to 1/2 her character level, healing as much as a paladin of her character level – 4.
Since they explicitly stack, does that mean you add them together into one big pool of lay on hands? Would a level 20 pain psychic with VMC paladin have 18+cha uses of lay on hands that heal 16d6?