Cook the Pasta
Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Reserve ½ cup pasta water, then drain and set aside.
Sauté the Shrimp
While the pasta cooks, heat olive oil in a large skillet over medium heat. Add garlic and red pepper flakes. Sauté for 30 seconds until fragrant.
Add the Shrimp
Season shrimp with salt and pepper. Add to the skillet in a single layer. Cook for 2–3 minutes per side until pink and cooked through. Remove from heat.
Combine Pasta and Pesto
Add the cooked pasta to the skillet with the shrimp. Toss with pesto, Parmesan, and lemon juice. If needed, add a splash of reserved pasta water to loosen the sauce.
Serve
Plate the pasta and top with additional Parmesan and fresh herbs if desired. Serve immediately.