I agree about seeing a Dr. to diagnose as well. Most of my clients have already been diagnosed (by the chiro or a physician) due to trauma, repetitive strain, etc.
Most of my clients are there as a result of auto accidents, some are referred by physicians. (I work in a chiro office) When I first see someone with whiplash sometimes some of the deep neck muscles are splinted and feel like beef jerky. I use hydroculator packs on them before & after deep work. I have found castor oil packs help too.