The querent is a moderate daily Cannabis user and has begun taking a pain killer. She complains of nausea and headaches.

She smokes Cannabis therefore it is that which “goes down her throat”, Saturn, L2.
The pain killer is L10, Mercury, her treatment.
Saturn is in positive mutual reception with Jupiter. So, no, cannabis is not bad for you. Quite the opposite, it is beneficial.
Mercury, the pain killer, L10, is in no negative reception with Jupiter so not harmful either.
However, Mercury and Saturn are in negative mutual reception and in a close trine.
The pain killer and Cannabis interact negatively. That is the problem. Jupiter retrograde hints at the “wrong” choice of combination from the querent’s part.
Answer: Cannabis is good. The pain killer is neutral. But you can take either one or the other. Both together cause side-effects.
Icing on the cake:
What planet is the natural ruler of pleasure and comfort (the opposite of pain)?
Venus.
What does the querent want?
Both Jupiter and the Moon are in Venus’ signs. She wants Venus: comfort/pleasure/no pain. She also wants Cannabis, as she exalts Saturn.
Venus in detriment and retrograde trines the ascendant. Translation: Venus cannot deliver; the situation causes discomfort/pain instead.
If we take Venus as L6 it tells the same story in reverse.
Outcome:
She stopped the pain killer. The nausea and headache are gone.