Bring a large pot of lightly salted water to boil over high heat.
Meanwhile, heat 1 tablespoon of the oil in a large saucepan over medium-high heat. Add the shrimp and cook, turning once, until they turn opaque, about 3 minutes. Transfer to a plate.
Add the remaining oil and the garlic to the saucepan and stir until the garlic is softened but not browned, about 30 seconds. (Be careful not to burn the garlic.) Add the tomato sauce, red pepper flakes, and black pepper and bring to a boil.
Reduce heat to medium-low. Return the shrimp to the saucepan and stir in the lemon juice. Cook just to heat the shrimp through, about 1 minute. Season the sauce with salt, and add more red pepper flakes if you want the sauce really devilish. Remove from heat.
Meanwhile, add the pasta to the water and cook according to the package directions until al dente. Drain well. Transfer the pasta to individual bowls and top with the shrimp and sauce. Serve hot.