Prepare noodles according to package directions. Drain and set aside.
Bring 1 ¼ cups water to a boil in a small pot. Add ramen seasoning packet, if desired.
Bruise lemongrass and lime leaves and add to pot along with galangal, tomatoes, shrimp, Napa cabbage and Nam Prik Pao.
Add about 15-20 cilantro leaves.
Boil until shrimp is cooked through.
Remove soup from heat and add fish sauce, chili powder and lime juice. Stir to combine.
Pour soup over noodles and garnish with more cilantro leaves.