Q: iPhone 6S won't charge

The problem started happening since a few days ago when I noticed that my phone 6S was charging very slowly. It was annoying but didn't think it was a big problem. FYI, I am using authentic Apple charger and cable which came with the phone when I purchased the phone. 

Since a few days ago, after being connected to the charging cable for a several minutes, it kept making the same chime sound over and over again as if I was trying to connect the phone and the cable again and again. Of course the phone wasn't charging at all. I tried to re-connect the phone and the cable several times; sometimes it worked and other times not.

Since yesterday, it basically won't charge at all! When being connected to the charging cable, nothing happens. Sometimes, the screen wakes up, but the lightning next to the battery sign doesn't come up. I did everything including:

-cleaning the charging port

-reset the phone

-update to the latest software

After a few frustrating hours, I found that charging works when it's connected to the laptop, not the wall. The problem persists though because I tend to charge my phone during the day at random places (e.g. cafe) without my laptop. I can't take my laptop with me all the time just because I need to charge my phone!

It seems that this is quite a common problem so I am not sure if I should take my phone to Apple or not. Does anyone else have this problem? Any word of advice, please? Should I take my phone to Apple?