Why don't I have enough storage on my iPhone?

I have a 16gb iPhone 5. I used up 13.3 gb so far and It tells me I don't have enough storage to take a pic anymore. I have lik 117 mb left but it's 16gb. What happened to the rest of like 2.7 gb. It's frustrating me.

Cause you use Apple

I have the same iPhone as you and for all it's storage that comes on the phone it takes up 2.7GB so really you don't get 16GB same with any ones phones memory

It has a 16 GB storage but all of it is not available because the ios (system) is installed and it takes up the space.
For the message that there is no space check out here maybe your problem is this
https://discussions.apple.com/thread/3406727?start=15&tstart=0

Hope this helps!

IOS. It has be to installed somewhere on the device of course.

You have to clean up to regain some storage.
Try deleting music, pics, vids, apps you don't need or use anymore
Try PhoneClean (desktop app) to clear data.

Should help.