I can't imagine why you would want to become a physician if your goal is bench or even clinical research at the PhD level. You will need the education and research training involved in getting a PhD in Pharmacology or at the very least PharmD. You simply won't get that by becoming a physician. Another thing to consider if you go the physician route is that you will be going through ~2 years of prerequisites prior to medical school, then 4 years of medical school, then as a bare minimum 3 years of residency and then another 2-4 years of the fellowship. There will a lot of hoops and there is no guarantee that you'll be able to get into medical school, residency or even the fellowship....all while possibly incurring a tremendous amount of debt.
Honestly, it doesn't sound like you've really looked into this. Is there a pharmacy or medical school near you? You ought to schedule a meeting with an academic advisor to discuss your educational options. Also ask about getting some experience shadowing or working in a lab and also a physician's office and perhaps sit in a few pharmacy classes, too.