IPhone 4 getting really hot, just replaced battery and still really hot?

I have an iPhone 4 and I have been having issues with it for a while now. It will get really hot (to the point where I can barely even touch it) and won't hold a charge. It's done this to me a couple of times. It fixed itself once, another time, I deleted my email account off of it and it was fixed… But this time, nothing is working. I've closed any opened apps, deleted my email, just got a brand new battery put in a few minutes ago. I just plugged it in and it's incredibly hot again and still not charging.

What's wrong with it? It my $500 or whatever phone just garbage now? Like… Ffs. I used to pay $80 for a flip phone that'd last me years… This is bunk.

Go to the store you bought it and claim for the warranty

Ok first off how much do you use your phone without breaks it could be that, also there could be faulty wiring and your wires connected to the battery are letting out the charge which would make battery drop fast and phone get hot

This might not help but did you know if you double click the home it shows all the apps you have running? Then if you swipe "up" on the app it will close it. If you don't remember to occasionally close apps that are running it can over use your phone causing it to be hotter but I feel like this is not your problem but with the actual phone.