Melt butter in a large pot over medium heat. Add the carrots, celery and onion and cook until just tender, about 5 minutes. Add the garlic and cook, stirring, for an additional minute. Sprinkle the flour over the vegetables and add the basil, oregano, salt and pepper. Stir and cook for 2 minutes. Pour in the broth and bring to a boil. Reduce heat and simmer, partially covered, for 10-15 minutes. Add the cooked chicken, egg noodles and half and half and continue cooking for another 10 minutes, until the noodles are tender and the soup is heated through. Serve warm and store leftovers in an airtight container in the refrigerator.