iPhone 5s camera app won't open and crashes from lock screen and control menu

Hello, I recntly got a Black iPhone 5s 16gb and it was working fine. Then sudenly the camera app started crashing after i took photos. Soon later the camera app wont open at all and if i try opening from the lockscreen the phone just reboots. Ive tried just resetting all settings just off the phone and nothing happened, so i decided to restore my iPhone to factory settings and still had no luck. I also had a problem with the flashlight it stopped working aswell (went gray on control menu) and all flashlight apps wont even. I also found out that my snapcat front camera (selfie camera works) and there is no 'swap button.

This is the second time Ive been suffering from a camera issue the first one was ery similar the shutter wouldnt open because there was no memory, but now ive got 9.1GB free so this cant be the problem. Other reviews i have read state that the phone has a hardwear issue and need to be replaced.