Tomato Chicken Noodle Soup

In a large heavy pot, heat the oil over medium high heat until hot. Stir in the onion, carrots, celery, 1/2 teaspoon salt and 1/4 teaspoon pepper, and cook, stirring occasionally, until golden, about 6 minutes. Stir in the stock, tomatoes with their juices and chicken, then bring to a gentle boil. Cook until the chicken is cooked through, 20 to 25 minutes, then stir in the pasta and boil until al dente. Season the soup with salt and pepper to taste, then serve.