Bring a large pot of salted water to a boil over high heat. Add the pasta, and cook until tender but still firm to the bite, stirring occasionally, about 10 minutes. Drain the pasta and set aside. (Follow the directions on your packaging.)
In a large skillet, add the shrimp, pico de gallo, and lemon juice. Cook, stirring frequently until the mixture is warm.
Add the cooked and drained pasta and alfredo sauce; gently stir. Stir in 1 cup Parmesan cheese; salt and pepper to taste. Heat for another 5 minutes on low.
Serve right away, sprinkled with ½ cup Parmesan cheese (optional), and garnished with chopped parsley!