Why does my phone's touch screen freak out?

I've had this phone for 2 years,and it worked perfectly,but recently,when i installed a apk ,when the phone's battery would reach 3%,the phone would ALWAYS keep holding down the multitasking button (bottom left of the screen) thus making the touch screen inoperable (since it's only alowed to read one of the two capacitive buttons below the

screen)Any help?Thanks in advance. Update 19/08/17 Now it never gets below 3% because i don't use it that much ever since i got my tablet.