HTC Desire 820 charging issue?

[AC Question]

I am having a few issues with charging my HTC Desire 820 as sometimes when I plug it in to charge when the phone is on it does not start charging and when I do eventually get it to charge then the screen stays on which is not supposed to happen as the screen is supposed to go black after about 20 seconds or so. Also sometimes when the screen is black and my phone is on then the screen display automatically comes on without me touching anything. This has been happening for the last three days as the other day I fell asleep with my phone by my bedside and my battery was quite low and when I woke up the next day I pressed the power button on the side of my phone and a battery icon appeared on the screen with a lightning bolt icon in it so I had to restart my phone and the problems have been happening ever since. If someone can help me please it would be great and help me resolve the problem.

 

[STARGATE]

I'm not familiar with HTC but, have you used a different cable and charger?
If that's not the culprit, a factory reset, after backing up your data in the phone, should be the last resort.
If none of that helps, maybe the battery is faulty.