Place chicken breasts in a single layer at the bottom of the slow cooker. Add crushed tomatoes, chicken broth, diced onions, celery, minced garlic, dried oregano, dried basil, and red pepper flakes. Stir gently to combine.

Cover and cook on LOW for 6 to 7 hours or HIGH for 3 to 4 hours, until the chicken is fully cooked through and tender enough to shred.

Remove the chicken breasts from the slow cooker and place on a cutting board. Shred into bite-sized pieces using two forks, then return the shredded chicken to the pot and stir to distribute.

Pour in the heavy cream and add the freshly grated parmesan cheese in two to three additions, stirring between each addition for a smooth result.

Add the uncooked ditalini or small shell pasta directly to the soup and stir to submerge.

Cover and cook on HIGH for an additional 20 to 30 minutes. Check pasta at 20 minutes. It should be tender with a slight bite. Do not overcook.

Taste and adjust seasoning with salt and black pepper. Ladle into bowls, garnish with fresh chopped parsley and extra parmesan, and serve immediately.