Into the pan add the lemon juice, stock, water, garlic, red pepper flakes, and capers. Return to stove and bring to boil, scraping up brown bits from the pan for extra flavor. Check for seasoning. If serving family style, place the spaghetti in a serving platter, place chicken breasts on top, and pour sauce over chicken and garnish with parsley. If serving individually, follow the same process into single portioned plates.