Well, you could try a factory reset. Kind of a PIA but it may cure it.
Another possibility since you can't pin it down to a specific app is that you may have a bad file on the SD card. I've heard of this before on this forum and others. Solution is to hook up the phone in disk drive and move all your files over to the PC. If there's a bad file(s), they will error during the transfer so you can get rid of them. Hopefully it's a file you put there like a pic, vid, etc rather than a system file. Once the card is empty, reformat it, move all the files back and reboot.