Heat the olive oil in a medium pot over medium heat.
Add the diced carrots, celery, and onion, sautéing for 5-6 minutes until the vegetables begin to soften.
Stir in the minced garlic, dried oregano, sea salt, and black pepper, cooking for 1 minute until fragrant.
Pour in the chicken broth and bring the mixture to a gentle boil.
Add the whole chicken breast and the dry orzo to the pot.
Reduce heat to low, cover, and simmer for 10-12 minutes until the orzo is tender and the chicken is fully cooked through.
Remove the chicken breast from the pot, shred it with two forks, and return it to the soup.
Stir in the fresh lemon juice and chopped parsley just before serving to maintain the vibrant flavor.