Welcome aboard. Hope you learn lots here.
Friend or Foe is useful [
www.friendorfoe.us],
and I second the motion to use the search function.
Also, look in your state's forum for state-specific (or in some cases city-specific) info.
Most national stores are neutral or welcoming. They don't want to turn away money & know that being against the Constitution will lose them lots of customers. (Also makes a more dangerous work environment, as evidenced by the variety of "gun-free zone" shootings across the country.)
The only national chain I can think of at the moment which is anti-rights is the Toys-r-us / Kids-r-us / Babies-r-us conglomerate. I'm sure other people will come up with more examples.