Sign out of iTunes & App Store under settings. Close App Store, Close itunes, Sign out of Music and close the app. Then switch off the device entirely just to be sure. Wait a couple of minutes not to jinx anything. Then turn on your device. Go directly and open only the MUSIC app by hitting that new problematic new music icon. Sign into your Apple account from MUSIC. Once signed in, you can go to settings to check under iTunes & App Store and you should be signed in. Did all this while on hold with the apple technician and by the time he got back to me, managed to give him the solution.
This helped me, i'm now able to login and download apps.
Thanks @@DiDA