In terms of the BSc or MSc, as long as it is listed under the undergraduate courses section, then they are basically the same, but for the MSc you will study a masters. MSc often have slightly higher requirements as well, but keep in mind that once you are at uni, you can always leave after you've gotten your BSc even if you did enter for an MSc course.
In your position I'd pick neuroscience, as I've heard that it's a slightly more interesting course, and although it may seem like a narrow field it is quickly evolving too.
Pharmacology is apparently a little less interesting, but of course, that is subjective.
Bear in mind that a lot of universities allow you to switch courses after the first year, I know quite a few people that started on a general biology course and then switched to something more narrowed down after the first year.
I would strongly recommend buying or borrowing a couple of books, one on neuroscience and one on pharmacology. Read them and see which one you find more interesting. That's how I picked my uni course (it's very effective). Although I quite liked physics, I just couldn't bear to read a whole book on it, whereas I loved reading about maths.