Cannot access Apple ID on iPhone 6 after iOS update 8.4.1

There's a problem with connecting to my Apple ID since updating my iPhone 6. I cannot update apps or use Apple Music and when I tap the 'iTunes & AppStore' button, it just freezes.

I can't log in or out of my Apple ID - I simply can't connect to it.

The problem was solved initially after I did a Reset, but now the same problem has recurred.

Is there another way to fix this?

QUICK RANT: Do I REALLY have to reset again and lose all my wireless and Bluetooth settings? I thought Apple was all about seamless services?