Just putting another method which worked for me (one time issue and fix, so it's a crap-shoot). I don't have the luxury of connecting to a computer via usb for anything except charging.
-properly flash a sufficiently different ROM (I had kitkat, so I flashed ICS)
-start ROM up, check if fixed (mine was not)
IF NOT FIXED, CONTINUE
-mount the SD card in your recovery (mine is WCX recovery)
-reboot your phone into the ROM
This method worked for me. I saw in a different forum that when this happens it's usually because a file that describes the partitions gets corrupted and that because ICS and GB partition the SD cards and internal storage in a different way than Jellybean or Kitkat, that flashing a different ROM (if problem is on ICS/GB, then flash KK/JB, and vice versa) will force an overwrite of the file in question.
This is not as easy as rignfool's method, and once my charge port arrives in the post, I will abandon this method and use Windows to repair the partition like a sane person
Also, it seems like all my media on the internal storage has been wiped, but wutevr :/