In a small bowl, combine the parsley, cilantro, red wine vinegar, lemon juice, minced garlic, salt, and black pepper to make the chimichurri sauce. Mix well and set aside to let the flavors meld for at least 10 minutes.
In a large bowl, toss the shrimp with olive oil, salt, black pepper, garlic powder, and red pepper flakes (if using) until evenly coated.
Heat a large skillet over medium-high heat. Once hot, add the shrimp in a single layer. Cook for 2-3 minutes on each side or until the shrimp are pink and opaque.
Remove the skillet from heat and drizzle the chimichurri sauce over the cooked shrimp. Toss gently to coat.
Serve immediately, garnished with extra herbs if desired.