In a large stockpot over medium heat, melt butter. Once melted, add shrimp, salt, and pepper, stirring to combine. Cook until the shrimp just starts to turn pink, about 1 to 2 minutes.
Stir in garlic, onion, and red pepper. Cook until vegetables are tender, about 3 minutes.
Stir in ginger and lemongrass, cooking until fragrant, about 1 minute.
Whisk in curry paste and coconut milk until combined. Whisk in Campbell’s Condensed Tomato Soup and vegetable stock until combined.
Cook, stirring frequently, for about 1 to 2 minutes. Bring the soup to a boil, then reduce to a simmer to thicken—about 8 to 10 minutes.
While the soup is simmering, cook rice noodles according to their package instructions.
Drain rice noodles and stir into the soup. Stir in cilantro until combined.
Serve warm with fresh cilantro and lime juice.