Is there anyway that I would be able to find out in my past life if I had already made a pact with any demon?
Akashic records, there might be a simple solution.
Some may not be aware of it, but the Rider Waite High Priestess card is supposed to help with memories of past lives, and represents all seven hermetic laws, and is symbolic of the subconscious.
In Paul Case groups, the seven laws relating to subconsciousness makes sense, the subconscious is a large personal power. It can cure and cause disease, health, wealth, poverty and so on.
Meditating on the image of the card, take in every detail, then focus on her eyes, and you may feel a shift.