Honestly, I don't know if it's a good idea to start a medical store, at least not until you're certified and legally can sell medication. Bear in mind, there are a lot of scam sites out there also selling medicine and other medical items to people on the web, and a lot of them are selling fake or knock-off medication, in turn harming people.
My suggestion, if you want to start a pharmacy, then you may need to actually learn medicine. Pharmacists go to school just like any other person. Because they need to know what the medication does, so as to not give someone the wrong medication. It's not simply about starting up a medical store. Sure if you sell off the counter items, that'd be fine, but if you're going to fill prescriptions, then you need to know why you're filling it.