No memory avaiable on my Galaxy S4

Speaking with experiance with a galaxy S4.

Try deleting the cache, from the storage menu.
Goto Storage->Internal Storage-> Delete Cache

Should empty up a lot of space by now, for more storage,

Goto Storage->Internal Storage-> Explore

Delete files named,

• .thumbnails




• .profigos




• .faces

These are temporary files created, you can delete them, it won't harm any of your data.