iPhone HELP: iPhone5S Annoying Problem!!!

[amflores]

Hello,

English is not my native language, so ...

Every 5 seconds or so, I get this irritating message on my iP5S:

"Start an ICloud Session
Type in your Apple ID password for xxxx@gmail.com"
​

I don´t use ICloud and can't remember the corresponding password.

The annoying message almost occupies the background image what renders my iPhone almost useless.

Both my iTunes and iOS 8.2 are updated.

What's wrong?

Cheers,

Flores