This didn't happen before so it's new. Every time the iPhone is out of battery and I plug it, it doesn't show up on screen that it is charging and keeps repeating the plunging sound. And it won't turn up if I let it still plugged and it heats so I leave it without charge for 2-5 days then when I check if the screen works before charging and displays no battery icon I will charge and it will return charging normally and opens. Do you think this has to do with the battery? or some bugs in the iOS? Please help me.
If the phone's battery is original, it is surely now defective due to age. Have it replaced. Continuing to try and use it may cause it to swell and physically damage other components in the phone.