Heat the butter in a large stockpot over medium heat. Add the onion, carrots, celery, 1 teaspoon of salt, and ½ teaspoon of pepper. Cook, stirring occasionally, until softened, about 10 minutes.

Add the garlic and oregano. Cook, stirring constantly, until fragrant, about 1 minute. Add the chicken, the bay leaves and the remaining salt and pepper.

Add the water, and bring everything to a boil over medium-high heat. Reduce the heat to medium-low and simmer, covered, until the chicken is cooked through, about 25 minutes.

Transfer the cooked chicken to a cutting board. Using two forks, shred the chicken into bite-size pieces. Return the shredded chicken to the soup along with the egg noodles. Continue to cook the soup over medium-low heat until the pasta is tender, about 10 minutes. Remove the soup from the heat and stir in the parsley and lemon juice.