I have a s5 and it overheats afer 5 minutes usually and battery drain very fast and charge very fast too.even i have an old sd card install and a apk file,do they make this symptoms or is the battery bad?
Samsung makes an app called Vitamins for Samsung, free download from the Play Store. It is very simple to use & comes with quite a few diagnostic tools, you can also clean the cache and/or ram, check for updates, FAQs, Tips & so on.
They also recommend an app called DU Battery Saver, free at Play Store. I didn't have battery problems but the DU app gives the battery a longer cycle.
Good Luck