To be fair, he was indeed a researcher in pharmacology in his previous life.
But now his main occupation is pharmacist, but he also has activities of diagnosis patients and magical powers to help with these two roles.
So he kind of fulfills all three roles: researching, producing and selling medicine, diagnosing and treating patients.
He is not so much "a pharmacist" as he is an all-purpose "medical professional". "Pharmacist" is just his official title.
It does feel like a movie "scientist". You know, "the scientist" type that specializes in biology, chemistry, nuclear physics, astrophysics, etc... all at the same time in one character. But this manga is not going that far since Pharma only specializes in medicine-related fields.