Walking and flying bug!

Hello, I would like to report about a bug that has affected how I walk and fly. My character will just randomly take off in a direction when I am flying. I have looked all through the settings and nothing unusual there. This also happens when I walk. My character will not stay still and it also affects my ability to build. I have the pocket edition of Minecraft if that changes or helps anything. To be more clear, when I walk or fly my character will just take off and start going a random direction without me doing anything. This also happens when I am just standing, I will be looking at my building for any mistakes and then my character just starts walking and won't stop. Thanks for your time and I look forward to hearing a positive reply that this could be fixed.