Chronic pain is associated with a loss of the normal capacity to know where your body is. Chronic pain is also associated with odd bodily feelings. To find out if people with chronic back pain had trouble ‘feeling’ their back, they were asked to draw on a piece of paper the outline of where they felt their back to be. This is a bit tricky to understand, but imagine you are surveying, in your head, how your body feels and then drawing its location. Anyway, you might have to read the paper to really get it. This is what we found: six out of six patients with low back pain, when they were trying to draw where they felt their back to be, said “I can’t find it” or “I’ve lost it”. When an independent investigator assessed sensory acuity on the back, sensory acuity was reduced in the same place the patient couldn’t feel properly. This study is very difficult to describe quickly. In short we think it demonstrates that chronic back pain is associated with distorted body image of the back. Here is the abstract: 
I can’t find it! Distorted body image and tactile dysfunction in chronic back pain
Abstract
G. Lorimer Moseley
Department of Physiology, Anatomy & Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford OX1 3QX, UK
The conscious sense of our body, or body image, is often taken for granted, but it is disrupted in many clinical states including complex regional pain syndrome and phantom limb pain. Is the same true for chronic back pain? Body image was assessed, via participant drawings, in six patients with chronic back pain and ten healthy controls. Tactile threshold and two-point discrimination threshold (TPD) were assessed in detail. All the patients, and none of the controls, showed disrupted body image of the back. Five patients were unable to clearly delineate the outline of their trunk and stated that they could not “find it”. TPD was greatly increased in the same zone as the absence or disruption of body image, but was otherwise similar to controls. The disturbance of body image and decrease in tactile acuity coincided with the normal distribution of pain, although there was no allodynia and there was no relationship between resting pain level and TPD. Tactile threshold was unremarkable for patients and controls. These preliminary data indicate that body image is disrupted, and tactile acuity is decreased, in the area of usual pain, in patients with chronic back pain. This finding raises the possibility that training body image or tactile acuity may help patients in chronic spinal pain, as it has been shown to do in patients with complex regional pain syndrome or phantom limb pain.
See full article at Pain 140,1 239-43
Moseley GL (2008). I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain. Pain, 140 (1), 239-43 PMID: 18786763