I started having this problem over a month ago. When texting pictures or uploading to Instagram, my phone would randomly shut down. I contacted chat support and did a factory reset. The problem continued to happen so I contacted chat support again and they sent me a new phone. It continued to happen. I contacted chat support again and they had me do another factory reset. It happened again, contacted support again and they sent me a new SIM card. It just happened again.
It's happened when I've had all my apps on my phone and when I've had none (I have downloaded none in the time this has been happening because what's the point in setting up my phone if I'm going to have to do a factory reset again or get a new phone?).
I currently have the following apps on my phone: Instagram, Twitter, Waze, PicsArt, CM Security, USAA, Hi-Q MP3 Rec and PayPal. If that helps.
After 5+ hours online with chat support and the trouble, Verizon gave me a lousy $8 credit for my trouble which I think stinks when considering I'm paying for premium service.