Why is my phone not charging?

There are a couple reasons.

1. Are you using the original cable and charging block? I have seen aftermarket chargers kill devices.

2. Make sure the port is clean, and the charging cable is seating firmly in place.

3. It's possible that the charge port or battery is bad.

The charge port is replaceable without soldering. You will need to open the back but, it's not a terribly hard replace. The battery can be tricky because of the adhesive but, again, not terribly hard to replace. If you aren't comfortable with doing either of these, take it to a local reputable shop.