Beef chuck is a huge primal cut that comes mainly from the shoulder section of beef, as well as parts of the neck, ribs, and the upper arm. The entire thing can weigh more than 100 pounds, and it makes up fully 30 percent of an entire side of beef.
The beef shoulder is a really complicated contraption, made up of a multitude of different muscles of various shapes and sizes. These muscles are used for locomotion, and for supporting the weight of the animal. The more a muscle is exercised, the tougher it gets. So shoulder muscles can be tough if improperly cooked.
The best way to prepare roasts is by briasing. To get the flavorful, brown outer crust sear it on the stovetop first.
A good way to get the tender roast meat is in a slow cooker (crockpot and dutch oven) or multi cookers (pressure combination). Just brown the meat as described, then add the vegetables, meat, seasonings, and stock.