No service after charging

As Daniel suggested, have you tried to punch in *#06# on the phone dial pad? If you can't see the IMEI displayed, then your phone likely suffers from a baseband IC issue.

However before that, you should try to eliminate any potential issues with the related antennae inside the phone. You could open the device and take a look to insure the antennas are all properly connected, especially if you phone was dropped just prior to the incident.

After you have eliminated antennae or network locks as the possible culprit, searching issues on the iPhone 6 series are usually related to the baseband IC. The baseband IC is very sensitive, just like the Touch IC's on the 6 Plus; it also suffers from poor quality traces and pads.

Go to your phone’s dialing keypad and dial *#06#. You should see the IMEI displayed.

If the IMEI is not displayed, the Baseband IC has to be reballed and two small copper traces (U1/V1) have to be rebuilt and solidified. This is commonly referred to as the “long jumper” solution. You can check out this answer (Service is "Searching" indefinitely) (by @teetopp) as it summarizes the issue really well.