Why doesn't my htc phone charge while plug in?

First, you need to check to see if the problem is with the phone - the battery - or the charger.

If you have a car charger, try to charge the phone with it. If it works, you'll need to replace your home charger.

If the car charger doesn't charge the phone - you'll either need to replace the phones battery or your home charger. (Sometimes the battery will go bad if you use a car charger not made specifically for the phone.)

If you replace your battery and it still doesn't charge you'll need to replace your home charger.

If after you've replaced the battery and the home charger and it still doesn't charge - your problem is with the phone and it will either need to be replaced or repaired.