Dice celery, onion, carrots, potato and bell pepper into 1/4-1/2" pieces
Heat dutch oven to medium high and add olive oil
Once pan is hot, add celery, carrots, potato, onion and pepper. Saute for 5 min until vegetables start to soften
Add tomatoes, parsley, garlic and red pepper flakes and stir
Add water and broth - cover and bring soup to a boil over medium low heat
Partially cover pot and simmer for 1 hour
Using a potato masher, mash some of the vegetables in the bottom of the pot
Add chicken to soup and simmer 30 minutes more
While chicken is simmering in soup- cook pasta
Right before serving, add cooked pasta
Serve with freshly grated Parmesan