Why isn't my phone charging fast enough?

[AC Question]

I have an Asus zenfone ZTE go phone that I bought for $80 at best buy, so it isn't the best, but it seems to work okay. My phone came with an Asus standard USB charger, that up until now worked great. Yesterday I woke up and my phone had been charging for 10 hours and was only at 80% and it was burning hot. Last night before I fell asleep I put my phone on battery saver deleted all the app windows turned off the wifi and turned on airplane mode I woke up 9 hours later and my phone was only at 75% and while it wasn't as hot as yesterday it was still burning. How do I stop that and make it charge properly again?

 

[Tesssssy]

I have an Asus zenfone ZTE go phone that I bought for $80 at best buy, so it isn't the best, but it seems to work okay. My phone came with an Asus standard USB charger, that up until now worked great. Yesterday I woke up and my phone had been charging for 10 hours and was only at 80% and it was burning hot. Last night before I fell asleep I put my phone on battery saver deleted all the app windows turned off the wifi and turned on airplane mode I woke up 9 hours later and my phone was only at 75% and while it wasn't as hot as yesterday it was still burning. How do I stop that and make it charge properly again?