1) I don't think its a bad idea to mention working in a pharmacy BUT I think what the best thing to do is choose the activity that you're MOST passionate about, spent the most time and effort in. If it was volunteering at a clinic, or being president of a club, etc. whatever, thats the one you should put down. A LOT of people will have some sort of pharmacy experience for that question. But if you put something unique, it'll set you apart from others and also give you something more to talk about during your interview. They'll know you worked at a pharmacy from your PharmCAS.
2) If it goes with your essay, don't cut it out. Just be sure to answer the question it asks. If the story directly is a part of your answer, then don't cut it out. I personally think that your thesis should answer that question and use the rest of the essay to explain and also I think its beneficial if you say what you want to do with pharmacy. The supplemental should be totally different than your PharmCAS essay.
Wait to see what Curt has to say about this. He's good at this stuff. He helped me get in!
Tom