Put chicken, stock and seasonings in the crock of a 5-6 quart slow cooker. Cook on high for 2-3 hours or low 4-6 hours.
Remove chicken from crock and shred with two forks, or cut if preferred.
Turn slow cooker to high, add cream cheese and 1 cup of the cheddar to the broth still in the crock. Stir until melted. Add salt and pepper to taste.
Add shredded chicken and uncooked pasta to the crock and top with remaining cheese. Cover and cook for another 20-30 minutes until pasta is cooked and the cheese is melted.