Screen went blank/black

[justmedwb]

I had my Samsung S5 in my back pocket with my other phone and sometimes i can feel that my S5's screen has turned on cause of the heat that it creates. Well yesterday i had it in my back pocket and when i went to go check it i thought that it was off or had died so when I got home I plugged it into the charger and the touch buttons on the bottom of the phone came on and I realized the phone was already on but i have no screen turning on. So after all my bumming I decided to hook it up to my laptop and use my side sync and see if i get a screen to show up on there. Well it does for a second then a warning box pops up that says " Unfortunately UI has stopped working". know I'm not sure if that has anything to do with my screen not working or not but I'm curious about the whole thing. I a just using the phone for internet and the camera. I do not have service to it and cant get it fixed that way. Also I have music and pictures on the phone that are in the phones memory and when it's connected to my laptop it don't allow me to open anything on my phone to take files off of it. If there is anything I can do someone let me know or am I completely screwed by having to pay for the phone to get fixed that I don't ever plan on using again.