Iphone 5S annoying popups

I keep getting annoying, "Sign In To iTunes Store" popups when attempting to buy songs etc..

This problem does not happen when I am on my PC.

No matter what I do in settings etc..I still cannot get rid of the popups.

Does Apple have a solution as I am running out of patience and

1.My iphone will be thrown in the sea

2.Never returning to Apple products