Cook your pasta 1-2 minutes shy of al dente.
Heat pan on med high, and add oil.
When oil is hot, add garlic, chilli, shallot, and lemongrass.
Saute until soft and fragrant.
Add oyster sauce, fish sauce, sugar, and Thai chilli paste.
Saute for 30 seconds, until combined.
Add clams, and stir fry until half cooked.
Pour in stock, and bring to boil.
Lower heat to medium, and cook till clams are cooked through, and opened up.
Add cooked spaghetti, toss to combined.
Remove from heat, and toss in basil and parsley.
Add juice of 1/2 lime, toss to combined.
Serve immediately with lime wedges on the side.