My iPhone says it is out of storage, but it's not?

My iPhone keeps notifying me that I'm out of storage, sometimes it won't even let me take pictures. But when I plug my phone into my PC, it says I have 3gb available on my phone! I've deleted most of my apps and pictures, and still when I view my storage through my phone it says I have zero kb available.

We got the app Dr. Cleaner. It is safe, reputable ( Trend Micro) and Really efficient is removing all those ghosts, fragments, etc, that clog your phone. Might not get ALL 3G back for you - but sure will get a LOT. We have had it on our two iPhone 6 phones, for 6 weeks - LOVE THIS!

Added - you might have to remove something to make room for THIS - but then you will have more than enough room to put that deleted app BACK.

Take it to the phone place you bought it.
They will fix it