Nevermind! I found a better, more code efficient way to do it:

var screenId = "Start";
function curS (string){
  screenId = string;
  setScreen(screenId);
} // curS stands for currentScreen

Now each time I want to use setScreen I can replace it with curS so it also updates my screenId and I can use screenId in place of the getScreen I had tried in my initial code.

if (screenId == "Start"){
 playSound("trendsetter-mood-maze-main-version-02-53-1004--AudioTrimmer.com-.mp3", true);
}

Thank you everyone for the help though :)