You can pre-order it from the Chinatown butchery.
Maybe it does not sell well and really perishable so not every
store carries the product.
Even the Italian eats pig's lung, I saw it at Italian markets
What do you do with cooked pig's lung?
it is usually for soup with bok choy and dried bok choy,
almond and bitter almond. Good remedy for chronic coughing.
I never use it for other cooking,
unlike beef lung which is more versatile.