Chronic neck and back pain can arise from a multitude of different pathologies. The spinal column is a complex series of bones (7 cervical, 12 thoracic, and 5 lumbar vertebra) that are each spaced by an intervertebral disc. Additionally the lowest aspects are the sacrum and coccyx or "tailbone."
Gradually over time or acutely due to trauma there can be a breakdown of one or more of these spinal levels referred to as Degenerative Disc Disease or Degenerative Spine Disease. When this transpires, the space where the spinal cord runs down or location where the nerve roots exit can become smaller. As the openings (Foramen) become more and more narrow, referred to as Stenosis, the likelihood that pain arises starts to increase. Classically, symptoms will present as axial pain that is in the middle portion of the neck or back and will be affiliated with Radicular nerve symptoms that travel down the arms or legs. This is commonly known as sciatica when felt in the leg. It is possible that symptoms present independently or in combination with each other. Depending on the vertebral level, side, and location of any disc or narrowing issue can determine the symptoms you may experience.
Aside from a disc and spacing issue, there can be added stress on small joints which are called Facet Joints. These are overlapping joints that can develop arthritis or Spondylosis and limit range of motion of the neck or lumbar back causing pain that tends to remain focal without significant radiation into the extremities.
Finally, "Doc, it hurts right here" as you point just below your belt line and off to the side. This can be a hallmark of Sacroiliac Joint Pain or Sacroiliitis which is the area where your tail bone connects to your hip bone.