Dennis,
A bite from any of the venomous snakes in your area should not be taken lightly. Though you can't ID it, if it was a constrictor you would not have the pain you are describing. I highly recommend you seek professional help before irreversible damage is done.
I have never been envenomated thankfully, yet I used to be a federally licensed venomous snakes keeper and you don’t want to risk permanent long term issues.
These are you like suspects, though it could be an escaped or turned loose exotic.
- Copperhead (found throughout NC)
- Canebrake Rattlesnake (found throughout NC)
- Eastern Diamondback Rattlesnake (found in southeastern NC)
- Pigmy Rattlesnake (found in southeastern NC)
- Cottonmouth or Water Moccasin (found in wetland areas in the eastern half of NC)
- Coral Snake (the rarest, found in the south and southeastern areas of NC)