iPhone says it's full even though it isn't

Hello,

I have an iPhone 7 and it keeps saying that my storage is full even though it is not. When I go check on Settings > General > Storage, it says that I only used 17,5 GB out of 32 GB (and when I plug it on my computer, iTunes says that I have 18.35 GB free). I keep doing the recommendations that are listed in Settings, but the same message of "Not Enough Storage" still pops up every time I try to download an app or take a picture. I know the 7 might be kinda old but everything else works perfectly.

My iCloud is full but isn't the storage on my phone different than the amount of space I have on my iCloud? If they are the same, is there a way to "separate" them?

Thank you for your help!