iPhone 5S rebooting with blue screen and SERIOUS "matrix" style randomly

hello all!

I recently bought an unlocked iPhone 5S from swappa.com and during the first week of having the phone it would randomly show a blue screen and then reboot back to normal. It would do that about 2 times a day.

The blue screen reboots have stopped, but now I have another issue. Ever since yesterday, my screen will black out and not turn on at all until I force reboot it by holding Home+Power for 20+ seconds. The first time it did it, it said the battery was dead when I tried pressing the power button, although my phone had a charge of at least 40%. I would literally lay my phone down for 10 seconds and pick it back up and it would not turn on when I pressed the home button to unlock my device. The last time it did it was last night, and I again had to hold Home+Power for 20+ seconds until it would reboot, and when it rebooted, it had a burned in image of my Photos app open along with the Apple boot logo surrounded by red burned color with a "matrix" style lines going through the screen.

I Have done a factory restore and it did it once again this morning.

Any ideas of what may be causing this? Can it be an app? I uninstalled Snapchat this morning and it hasn't "blacked out" on me yet, but I didn't think an app could cause an issue that seems hardware related, like maybe the digitalizer going bad?

thanks for any and all help!