after tinkering with system tuner, phone stuck in boot

I am almost a complete noob but want to learn everything i can to really "own" my phone. Im on an SPH-L720 4.4.2 and had root with [CF-Auto-Root-jfltespr-jfltespr-sphl720.tar.md5] (i think) though it might have been CF-Auto-Root. Everything was fine until I screwed around with some settings in SystemTuner . Now the phone is stuck in boot loop and sticks at the yellow Sprint screen. I've been able to flash back to stock ROM i think, and keep getting the PASS in Odin but keeps sticking at boot. I must have somehow got to TWRP 2.8.4.0 cause I'm going through that but really dont know what to do. Still can't use phone. Any help is seriously needed.