why can't i buy from itunes store worldwide, even when i have a credit card? Why am i restricted to my own country?

Sorry... But... You cannot use other countries itunes stores.

You must be within the Country with a Valid Billing Address and Credit Card for that Country to use the iTunes Store of that Country...

Also... See this Discussion...

https://discussions.apple.com/thread/4437103?answerId=20034050022#20034050022

And there is this...

http://www.apple.com/legal/itunes/us/terms.html#SERVICE

dondon1980 wrote:

Therefore there's no way I can buy a certain track featured in another country's iTunes Store?

Correct.

dondon1980 wrote:

...

What abt if I buy an iTunes card from that particular country?

Will I then be able to download from that particular store?

Sorry... This will not work.

iTunes gift cards are Only Valid in Country of issue.

dondon1980 wrote:

Thanks for your help.

You're Welcome.

dondon1980 wrote:

But knowing this kinda sucked....oh well.

Basically it's because content is controlled by the Copyright Owner...