apple id is only valid in us store

If you intend to change country or region for your Apple ID (e.g. emigrating), then you will need to have the account balance zero’ed, and subscriptions ended.

If you did not intend to long term change the country or region for your Apple ID, then you can have it set back to its previous setting (correcting the mistake), by signing out for the iTunes Store, and then sign in again. Then the Store region should match the Apple ID region again, and your Apple Music service should work again.

It is not at all easy to accidentally change store. You would have to intentionally enter a payment method for another country. Most likely you tried following a link to an item in another country's store (common in web blogs about music) and this messed up your phone's region settings. Here's a discussion about a similar issue inlcuding recommendations from a Community Specialist:

Apple music - Apple Community