Google Nexus 5 :: Phone Extremely Slow And Stutter From Boot

I replaced myself the screen (preassembled screen+digitizer+frame). After the replacement everything worked perfectly for like two hours when i rebooted it, from then on it is extremely laggy and stutters from boot animation, and when I press the power button (or when the screen shuts down), the phone itself shut down. In bootloader it doesn't seem to have problems.

I checked every connection inside the device (I've disassembled ad reassembled it several times).. thinking of a software problem, I've flashed marshmallow stock rom frist, and kitkat 4.4.4 then... but it's the same with any factory image.

with a lot of patience I set up a google account and downloaded cpu-z to see if maybe temperature sensor where giving wrong information to the system, but they're fine and everything seems to work propely aside from the stutter.