Bring a large pot of salted water to a boil. Cook the angel hair pasta according to package directions. Drain and reserve.
Heat a large sauté pan over medium heat. Add the oil and shrimp. Cook, stirring and turning until the shrimp are mostly pink with some grey remaining (about 2 minutes). Add the garlic and continue to cook until aromatic and starting to brown (about 30 seconds).
Deglaze the pan with lemon juice and chicken stock. Toss in the capers and spinach. Cover the pan and allow the spinach to wilt (about 2 minutes). Add the pasta and toss.
Taste and adjust seasoning with salt and pepper. Divide between 4 bowls.