Blue Screen Of Death - iPhone 5S

I have an iPhone 5S two months over a year already.

10 days ago I started having the Blue Screen of Death. After trying other recommended solutions that didn't work, I reseted my iPhone to original settings and downloaded very few apps (whatsapp, Facebook and couple others). I still have the BSOD but not really often, once or twice a day instead of the phone not working for more than 10 continuous minutes.

I'm fearing that the issue will again be critic soon, any suggestions??