I recently purchased a NFC shield for my arduino that involved me having to solder the headers onto. When the shield is attached to the board and I plug it into my computer I hear a sizzling sound and the board does not operate. Also I used flux on the headers while soldering. Please help.

 

Sounds like you have a solder short. You might find it with an ohmmeter.

Sometimes you can just heat a solder blob, then hit the board to your work surface and watch it fly off.