Why can't I listen to podcasts/music without phone acting possessed?

I know the question title is odd, but I can't figure out what is happening to my Note 5. I listen to podcasts and music on it for several hours a night at work. The Note 5 is usually in my pocket with headphones connected. After a couple of hours or less, I start to have problems: The app running the podcast will shut off automatically; sometimes it will shuffle to the next podcast before ending the first one; sometimes it shuts the podcast app off and start playing music from my playlist; sometimes the volume shoots to maximum; sometimes the S Voice app comes on; sometimes my phone shifts from vibrate to ringer on; sometimes it is a combination of the above problems, and getting control of the phone is difficult.

I've tried things like powering the Note 5 off to see if rebooting it helps. Sometimes it stops it, sometimes the problem is still there persistent. I thought perhaps I had some malware or virus affecting my device, so I installed Malwarebytes and Avast Antivirus. While some malware was discovered and dealt with, the problems continued. I read that maybe I need to clear the cache in safemode, so I tried that, but the problem remained. I thought maybe it could be the podcast app itself (I use Podcast Republic), but because the problem included music files and other phone functions, I'm not sure if that is true. I'm going to try a different podcast app. But I'm not hopeful.

Does anyone have any ideas? Anything would be helpful. Thanks.