In the slow cooker, stir together the garlic, bell pepper, crushed tomatoes, chicken, broth, onion, cheese, basil, oregano, and red pepper flakes. Cook on high for 3 1/2 hours, or on low for 7 hours.

Transfer chicken breasts to a cutting board and coarsely shred them; return them to the slow cooker; stir in the pasta. Cook on high for 30 minutes longer or until pasta is cooked al dente.

Serve garnished with more Parmesan cheese and chopped basil or parsley.