Help me get my phone working

on my phone this message came up and it will not go away. It won't let me turn it off and I plugged it up to my MacBoook Pro and it still won't go away. The message says: "This iPhone hasn't been backed up in 2 weeks. Backups happen when this iphone is plugged in, locked, and connected to Wi-Fi. How do I make this go away so I can use my phone?! This is an iPhone 5 by the way.