Storage problem in Android

Sep 1, 2017
My sd card has 14 MB free space,
But some apps those are movable to SD card are not moving .
Also no data is uploading or downloading on WhatsApp or share it,
But still playstore is working properly.
Moreover when I capture screenshot then notification comes that "screenshot is not captured, storage may be in use."
One more thing that I had noticed is, when I clear cache of the apps,it's not working.
I have also given the storage preference to SD card.
What should I do then????
Please give some suggestions.
My phn version is 4.4.2