These are related. You have a chronic pain syndrome probably from degenerative disc disease and facet syndrome (your osteoarthritis).
THe condition you describe, where touch was once pleasurable and is now painful is called allodynia -- a symptom of chronic pain syndrome.
Chronic pain syndrome or central pain, is a disease of the nervous system caused by untreated pain.
My advice is to seek out a board certified pain specialist. These doctors hacve the credentials MD (or DO), DABPM.
The DABPM tells you this doctor has a diplomate from the American Board of Pain Management.
THis is advanced specialty, usually associated with anesthesia. These doctors are trained in chronic pain, the use of opioid analgesics, and interventional techniques.
One procedure that will help the pain of your arthritic facet joints is called a medial branch neurotomy, or more commonly known as RF Ablation.
In this ingenious procedure, the practitioner removes the nerve tissue providing sensory innervation to those painful joints. With no nerves to carry the pain signals through the spinal cord to the brain, you experience less pain.
I have this procedure done annually (because the nerves regenerate). It reduces my low back pain by approximately 50%.
This is an outpatient procedure that takes about 30 minutes, and is performed under so-called waking anesthesia. After the procedure, you go home. Your back will hurt for a week or so, but that's from the inflammation caused by the procedure. Once that resides, you'll have reduced pain for 6 to 18 months, depending on your doctor and your condition.
You can find a DABPM at a university teaching hospital with a pain clinic, or via an internet search, as many are in private practice.
The allodynia is a condition that may stay with you, but can be treated. If you keep your pain reduced with procedures like RFA and medication, it can go away with time. Again, a DABPM is the specialist to treat this condition.
By the way, the OP you're writing to hasn't been here since 2010.
Best wishes.
I too get this sort of involuntary jerking, I have only just found your comments and am disappointed to see there are no answers to why this would happen. I have had severe lower back pain and found out that I have osteo arthritus. However, I don't believe it's connected, but my back is now very sensitive and even the lightest brush can sometimes make me jolt. I feel achy and bruised too, but it only seems to be my back that makes me jerk, my partner thought I was doing it on purpose at first, but now he knows I am not. It is embarrassing as it makes me moan loudly everytime. The doctor doesn't give any answers either why this occurs. Sometimes you feel you can diagnose your ailments better yourself, but this has me foxed too.
All the best. Margaret Green.