It IS a right in the sense that you have a right to access it. You have a right to receive health care, purchase food, and access public spaces as part of your right to life (I.e. preservation of personal health), liberty (i.e. freedom of movement), and the pursuit of happiness (i.e. personal autonomous decision-making).
Your right to access the public marketplace doesn’t require that someone else builds a store — but it does mean that if they open their store to the public they can’t arbitrarily shut you out. And neither can the government use licensing or permits/zoning/etc. processes to facilitate them doing so, except for extremely good safety reasons (not capricious, exaggerated, or manufactured ones).