While there may not as yet be enough clinical evidence, it may be suspected that stiffness of the neck muscles associates with the pain of the tooth.
The majority of the scenarios could be attribute to the molar teeth perhaps previously treated. The major muscles that pull the tooth root (the interior surface of the mandible) would be the mylohyoid. The associated muscles would include the digastric, the omohyoid, the stylohyoid, and the sternohyoid that connect to the hyoid bone.
If it applies to you, the muscles that are affecting those neck muscles need to be released.