"Cannot connect to itunes store"

I am using iphone 3gs running ios 6.1.6 . When i open itunes app in my iphone there is always a message appear showin "cannot connect to itunes store" . My Internet Connection is very good . I have tryed different internet connections . But its not working . But when i change my region settings in apple ID then its succesfully connect to itunes store but when i choose my country Pakistan then its not working. Please help me .