iPhone pauses or plays songs when the headphone plug moves
It happens because a quick jog of the plug causes a short interruption in line level. It's the same with headphones -- Apple or otherwise -- that include a play/pause button (usually place on the cable itself, where it splits to go to each ear). That button functions in exactly the same way, by momentarily interrupting line-level on the phone's cables. iTunes starts playing because it assumes the interruption from plug movement (or a dirty plug) is a play/pause signal. As a simple demonstration, start iTunes playing something and wiggle the phones jack, same conditions as make iTunes launch and play, only if it's already playing this will make it pause.
I've tried many of the fixes on here, NONE of them worked... I noticed my phone was showing "Less than 20% battery"... Maybe... Took it home, charged it.. No more pausing... Maybe the issue is no more than that! I'm using the same headphones, and the podcasts have been playing without issue...
Good luck!