If I started a chocolate shop, could I buy chocolate at the store to mold and sell as my own?

I was thinking I'd have to learn how to make my own chocolate but a guide to beginning your own chocolate business said to buy chocolate at your local grocery store and do whatever you want with it. Is that legal? I thought using their chocolate would be like stealing their recipe. Isn't that breaking trademark laws or something? Or can I use it as long as I say it is Hershey's chocolate(or Symphony, Lindor, etc)?