I don't know what it is but it just has to be neurological.
Is it a shoulder tic or a semi volountary repetative movement I have.
I can stop it if I want to (or have to to hide it) but I get some strange satisfaction out of tensing and releasing all day long. Sometimes I will tense it so much that the tendons pop.
Sometimes by the end of the day I am completely sore and exhausted.
It has been a nagging ocd for about 9 years.
It is intensified during periods of stress and anger but often times for no reason at all.
Used to be mostly on my right side and included the right hip but now seems to be spreading to the left.
I am sure that I will have crippled myself in 15 years by wearing away the cartilidge and tearing the tendons and ligaments and causing nerve damage.
I think it started when I was a teen taking lots of slapshots playing hockey thus straining the area.
When I was 8 or 9 i noticed a tendancy to have small rare ocd type rituals, nothing severe...just a quick count with a blink or two and some swallowing. I don't notice it now except for the shoulder/hip problem.
It's really annoying the crap out of me and I am considering perhaps an ocd medication to see if it can help.

Sounds like OCD, which is actually an anxiety disorder. The repetitive tic relieves the anxiety. Look at medications/programs that relieve anxiety. Normally, OCD is low serotonin and dopamine, where the serotonin is even lower than the dopamine. The dopamine is usually low in the brains prefrontal cortex, the area that normally enables inhibition of thought and action, and high in other parts of the lower brain.

The best simulant for OCD/Anxiety/ADD is Dexedrine. In children, dexedrine often solves all the problems by itself. In adults, things get more complicated. For Adults there is a drug called Milnacipran that is sold as Japan's #1 anti-depressant that has a pharmacological profile that fits the anxiety/ADD co-morbidity. 100mg/day is the minimal therapeutic dosage. Adding a small amount of dexedrine to Milnacipran may be a good combination.

Please seek a diagnosis from a well-trained medical professional. We can speculate, based on the symptoms you describe, but things like medication side effects and trauma can often mimic OCD symptoms.

I just did a search for this same thing, and came upon this site and your post. I could have written your post myself, mine is with my left shoulder and I do exactly what you describe. In the past it has been eye twitching or stomach tensing, but it has been the shoulder thing for a few years now. I also always considered myself "ocd-ish" but I recently decided to go to a psychiatrist to see what she would say and I was diagnosed with ocd, the shoulder thing is a compulsion. I am on zoloft now which has helped other symptoms a little, but not the shoulder yet. The psychiatrist said it would take up to 3 months to see max benefit. I just wanted to share that you are not alone! By the way, I am also in Chicago and am about your age. Small world. Good luck with the shoulder, if you can figure out how to stop I would love to know how too.