Bring stock to a rapid boil, and add chicken.
Bring back to boil then reduce heat to simmer.
Cover, and allow to chicken to cook for 5 minutes.
Add coconut milk and straw mushrooms.
Then add lime leaves, garlic, shallot, lemongrass, chilli and galangal.
Season with fish sauce and sugar.
Bring to boil, cover and lower heat to simmer.
Allow to simmer for 4-5 minutes, until broth is infused with spices.
Remove from heat, and stir in lime juice to taste.
Serve over Thai rice stick, and garnish with chopped coriander leaves.