Hello,
This sounds like a region setting issue and not an actual change in country. This can sometimes happen if you find a link on the web that points to an app or a media item in another country's iTunes Store. Here's how you can correct this:
Sign out of the iTunes Store [ https://support.apple.com/HT203983 ] and sign in again to get the iTunes Store region to match the region to which your Apple ID country is set, as described in this post: https://discussions.apple.com/thread/250611340?answerId=251184940022#251184940022
1. Go to: Settings > Account > Media & Purchases > View Account > Country/Region
2. Make sure it is set to your normal country.
3. In the "Media & Purchases" menu, sign out and then sign in again.
The above is a simplified version of that in the support document 'Change your Apple ID country or region' ( https://support.apple.com/HT201389 ) except you shouldn't need to do the extra steps involved when you have done a true country change.