pamjitkudhail, there are a couple possibilities. the first one that I would definitely look at is the battery. I am somehow convinced that your battery is at the end of its lifespan, and may surely have been discharged below the charging threshold. Start with that, replace the battery. Should it still heat up, you may have trouble with the power management IC, which will require you to solder a very small part on a logic board. Of course, also make sure that you have a good USB cable and that your dock connector is clean, that the pins are not bend, broken or corroded. If you are sure that that is okay, start with a new battery. This guide is for the battery. Hope this helps, good luck.