The first thing to consider is this, did the game run fine recently? Was there a update to your software before you noticed the game start to act wonky?

If you have been able to play the game fine until recently either there was a software update that is causing the issue, possible software corruption, or your phone hardware is starting to give up the ghost. If possible, the best solution is to backup your personal data and factory reset your phone. Then because it will be like having a new phone, you'll see if it is software or hardware issue.