Samsung Galaxy S3 — Issues with Boost S3 SPH L710

First let me tell you I sorta know what Im doing but dont understand a lot of terminology used on forums and dont go too deep into messing with phones. On that note, I have a Galaxy S3 from Boost that froze up during an update and stopped on samsung screen. I followed some online instructions and downloaded Odin, then found a stock Sprint (not Boost like I wanted) file and successfully installed it. Everything works fine except that the battery is draining pretty fast and gets unusually warm during charging. Im wondering if its because of what I put on there. I purchased a new stock battery and still have same issues. So...... Could what I put on there cause these problems? Do you have or know where I can get the original Boost S3 stuff to put on there? Anyways Id appreciate any help or suggestions you might have.....