Why does my videos keep crashing?

So I've had this phone for a couple of months working perfectly with no trouble whatsoever. But recently when I open the YouTube app the video just keeps pausing after a few seconds and the Facebook app sometimes just shows a gray screen with the audio of the video. This doesn't happen on the explorer (or Chrome) though: video runs like always.

I've reinstalled both apps but didn't work... and this happens both with or without headphones

Is it a process that keeps interfering? What should I do?