"Shelter in Place" laws

Hi! I'm not exactly sure how "shelter in place" regulations are legal - or Constitutional. Apparently, individual Governors of each Sovereign State can =order= citizens to stay in their homes except for things like groceries, drugs, and other medical necessities. OK - someone tell me why =any= government official can do this. These "shelter in place" regulations restrict my God-given freedom - a freedom guaranteed by the United States Constitution. What happened to "Life, Liberty and the Pursuit of Happiness"? 'Liberty' should mean I do not have to listen to these orders. They are also restricting my 'pursuit of happiness' by restricting me to my home. I have heard that it is possible for police to issue a citation, in the form of a misdemeanor, which could, in some cases, remove my driver's license! Please! If someone knows why this is legal - contact me! Bruce