Pat the shrimp dry with paper towels and season lightly with salt and pepper. Slice the bell peppers into thin strips and finely chop the garlic. Have the lemon juice ready.
Heat a large skillet over medium-high heat and add the olive oil. Once shimmering, add the sliced peppers and stir-fry for about 3-4 minutes until they soften slightly and develop some charred edges.
Push the peppers to one side of the pan. Add the shrimp to the clear space and cook for 1-2 minutes per side until they turn pink and opaque, releasing a fragrant aroma.
Add the minced garlic to the shrimp and peppers. Stir continuously for about 30 seconds until fragrant, being careful not to burn the garlic.
Pour in the lemon juice and sprinkle the red pepper flakes. Toss everything together quickly to coat the ingredients evenly, and cook for another minute until the peppers are tender and slightly caramelized.
Taste and adjust the seasoning with more salt, pepper, or lemon juice if needed. Serve immediately while hot, garnished with fresh herbs if desired.