When stewing beef, does it get hard before it gets tender?

Yes, if you're making a pot roast or stew with large chunks of beef, the meat will become hard as it initially cooks, because the proteins within the meat are being cooked and coagulating, sort of lumping together. If you're cooking the meat slowly, in a dutch oven over the stove or in a crock pot, the slow, steady heat will start to break down the collagen within the beef, kind of like a binder agent that keeps things together, and that slow heating process will help melt the collagen away, loosening the beef up to a more tender state, and also thickening the stew as well.