iPhone 5s works by his on

Hello,

I live in Ecuador and I my mom bought me an iPhone 5s last tuesday, I opened it and has flaws, sometimes if I touch the right side of the screen is like the screen ignore what i'm touching, sometimes it happens with all the phone, so i have to turn it off/on so then I could use it. Every morning at least for two hours the cell ignores any of my comands, is like it's possess, because it's working by his own, I have to wait a lot of time so then I can use it. This is normal or what?

Anybody know if I can change my iPhone in Europe instead of doing it in the US? because in Ecuador they aren't allowed to change phones if they we don't buy them here.