Looking to start in pharma sales, advice?

I've read a few threads about people wanting to break into the pharma sales ind, but haven't had my questions answered and I'm hoping someone could help. A little about me for qualifications: I received a Bachelor's of Science in Kinesiology (otherwise known as Exercise Science) with a minor in Business, and am currently working on my Master's of Science in Organizational Management. I have only been in sales for about a year but of the two places I have worked (commission-only positions) I have excelled and been number-1 company wide on several occasions.

-It seems like the general advice is to stay away from this career, why is that? I see the median salary is the largest its been and of the people I know who are in the business (albeit two, but they are very successful/wealthy), they highly suggest it and want to help me get into the field.

-What should I learn as far as information goes so that I could be prepared for a psr position?

-What would I need to do to break into the field and who would be a few good companies to gun for? I've read that Pfizer wouldn't hire me because I am not seasoned, so maybe Lilly or a daughter company of a bigger one?

Thank you all for the help!