Heat olive oil in a large pot or dutch oven over medium high heat.

Add in the onions, carrots, celery, and garlic, and cook until vegetables begin to soften, about 5 minutes.

Add in the tomato paste, and stir to coat the vegetables. Cook until the tomato paste begins to darken a little, about 2-3 minutes.

Stir in the broth or water, lentils, paprika, salt, and pepper. Bring to a boil. Add in the chicken and cook for about 5 minutes. Turn heat to medium low, cover, and continue to cook for about 35-45 minutes, or until chicken is cooked through and lentil are tender, but not mushy. Check periodically to stir, and make sure that the soup isn’t boiling or bubbling too much.

Using two forks shred the chicken breasts. Stir in spinach and lemon juice. Cook until spinach wilts, about 2 more minutes. Turn off heat. Stir and lemon juice and season with additional salt and pepper as desired.