Heat olive oil in a large, heavy-bottomed pot over medium heat. Add the diced onion, carrots, and celery, cooking for about 5-7 minutes until the vegetables begin to soften and the onion becomes translucent. Stir in the minced garlic and cook for another minute until fragrant.
Pour in the chicken broth and nestle the chicken breast into the pot. Add bay leaves, oregano, thyme, and red pepper flakes if using. Bring the mixture to a gentle boil, then reduce heat to maintain a steady simmer.
Cover partially and simmer for 25-30 minutes, or until the chicken is completely cooked through and easily shreds with a fork. Remove the chicken breast carefully and set aside to cool slightly.
Once the chicken is cool enough to handle, remove and discard the skin and bones. Shred the meat into bite-sized pieces using two forks. Season the broth with salt and pepper to taste.
Return the shredded chicken to the pot and bring the soup back to a gentle boil. Add the pasta and cook according to package directions until al dente.
Remove the bay leaves and stir in fresh lemon juice and chopped parsley. Taste and adjust seasoning as needed.
