In a large pot, heat the olive oil over medium heat. Add the diced onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic, carrots, and celery. Cook for an additional 3-4 minutes until the vegetables begin to soften.
Add the chicken breasts to the pot, followed by the chicken broth, thyme, oregano, and red pepper flakes if using. Bring to a boil, then reduce the heat to low and simmer for 20-25 minutes, or until the chicken is cooked through.
Remove the chicken from the pot and shred it using two forks. Return the shredded chicken to the pot.
Stir in the heavy cream and frozen peas. Simmer for another 5 minutes until heated through. Season with salt and pepper to taste.
Serve hot, garnished with fresh parsley.