The people who claim that stones are a byproduct of the oil and Epsom Salts have never come up with any chemical reaction that can take place in the (living) body that explains their theory. Hveragerti was the closest, except for the fact that his theory only could account for microscopic amounts of saponification, nothing on the order of large amounts of stones.
Not a single person has ever successfully concocted a stone outside of the body with oil, Epsom Salts , or hcl acid.
What you are experiencing is continual formation of stones. There are many factors that can contribute to this. It sucks, but don't alter your rational perceptions of reality just because it sucks.