My apologies if this is the wrong place, hopefully it's not...
I have a Sony Xperia cellphone (and I rarely use cellphones other than to call to begin with; my apologies for being an idiot!) and got an app game for it that I found quite fun (a Facebook-ish game, just made... Y'know, GOOD).
As I entered an area in that game, for some reason the game just froze (I can't interact with anything).
I have the exact same cellphone (and luckily, I had encountered the same problem as you had once before!)
What I did was this:
Go to the menu on your cellphone, click on the 'Settings' button, go to 'Apps' (or whatever it says in your language), click on the app that won't work, choose 'force closeure' (or something similar). Once done, start the game back up and it'll work again. Hope this helped.
You might lose some data (hopefully not! If you do, sorry!)