Iphone is really hot and has only just turned on after 2 hours on charge?

Iphone is really hot and has only just turned on after 2 hours on charge? It hasn't come on for 2 hours, it was charging as it usually turns on, it has finally turned on and is boiling hot?

Sounds like you have either covered up the openings in the phone, where the hot air escapes. Or you are currently using too much applications at once or using really complex apps for a long time.

Try not to cover the little openings with your fingers, close any apps your not using anytime soon and don't use complex apps for long periods of time.

Could be a problem with the battery itself.

When a battery charges, because the charging process is a chemical one, it will generate heat, which would be noticeable, but not to the point it is hot.