Bring stock, galangal, and 1 lime's juice to a boil. Simmer for 20 minutes. Add fish sauce, dried chiles, fresh chiles and onion. Simmer for 10 minutes. Add chili paste, tamarind juice and mushrooms. Bring to roiling boil. Add shrimp, salt, pepper, tomato, and green onions. Simmer until the shrimp are done about 5 minutes. Remove from heat, add cilantro and lime juice. Serve with rice.