IPhone stuck and keeps resetting?

I seriously have had it with this iPhone. (iPhone 4s) I've purchased it 2 Decembers ago months after it came out. 2 months ago it has the weird problem out of know where. So I've heard of people's phone battery's stuck or it keeps restarting but oh no! Mines got the double whammy! So some days since I don't know what battery I have it will die. Doesn't show when it's gonna die so it just does. Then I plug it in and it turns back on immediately. Then 3 minutes later it resets. Over and over again. It will do it all night! But when I unplug it, it does it for about an hour. Then it stops. Also I noticed when I'm typing something or something else it freezes sometimes. Like the phone can't keep up with me anymore. I've restored it many times already (started as new iphone) and had the screens replaced not by apple but that should affect it. It has been perfectly fine after I had them replaced(about 8 months ago) and when I do the reset by holding the home and off button together it's still the same and then goes back to resetting over and over again for about an hour. So now in just stuck. I bet apple will not replace it if its already been replaced by an aftermarket store. My upgrade isn't coming up any soon either. Just wanted to see if there's anymore answers out there

Try to restore it to it's original settings, it if doesn't work then I think its a hardware issue.