My payment method declined!!

Using a country's store when not in that country isn't allowed by the store's terms of use. Until if/when Apple open an iTunes Store in Afghanistan, or you move to a country that has an iTunes Store and you have a billing address there, you won't be able to download iTunes content. If you want to leave feedback to Apple about it : http://www.apple.com/feedback/

What are you trying to use as your payment method, credit or debit card ? If it's a debit card that might be why, not all seem to still be accepted by iTunes, and they might no longer be accepted at all in some countries. Do you have another card that you could try (preferably a credit card) ?

For a card to have a chance of being accepted it needs to be registered to the same name and address (including format and spacing etc) that you have on your iTunes account, and have been issued by a bank in the country where you are (and therefore the country which is on your iTunes account).

Does the card meet the requirements that I included above ? Do you have another card that you could try, preferably a credit card ?

If you mean this no my iTunes address and name is not same with my card

Have you tried correcting the name address on your iTunes account ?

You cannot use the US store unless you are in the US, and Apple haven't yet opened an iTunes Store in Afghanistan - when you are back in the US (with a US billing address) you can use its store.