Under what constitutional power is the federal government authorized to force you to close your business? Under what constitutional provision is the federal or state government executive allowed or authorized to force people against their will to wear something over their mouths and nose? Same question for how they can say you must “shelter in place” when you are not even the one who is sick?
May I also make a simple prediction: there will be numerous lawsuits about the way those laws were carried out. Some of those suits will advance all the way to the Supreme Court -- the final arbiter of what's constitutional or not. No doubt, some of the more draconian measures will have been ruled unconstitutional. OTOH, most of those measures will be ruled constitutional. The latter is (IMHO) a safe bet because these laws have been around so long, that they've survived many challenges.
The key thing that you, and several other posters here, are missing is that, while these laws limit some of your freedoms, they aren't the only laws that do so. For instance, you have the right to bear arms (and, this Canadian envies your 2nd Amendment, given what our idiot PM has just pulled). You have the right to bear arms; however, you do not have the right to stroll down the street with a revolver, blithely playing Russian Roulette by pointing the gun at passersby. Given that carriers can be asymptomatic, everyone should assume that their (figurative) 'gun' is loaded. It's that simple. Your civil rights do not trump others' inherent right to life.