I've had it for some years, comes and goes over an 18 month period, basically keep it moving (possibly physio), i tend to only take painkillers/anti-inflammitory when pain is bad before bed.

It could be all sorts of stuff.
It sounds similar to when I had an inflamed tendon some years ago - it hurt all the time but was incredibly painful if I lifted my arm out to the side and upwards.
The doc fixed it (on that occasion) with a shot of some evil goo into the shoulder - it ached like hell for a couple of days and then felt as good as it had ever done.
The next time it happened, a few years later, the injection had no effect at all and it was sorted out with physio.

Equally, it could be something entirely different.

Best to get it checked out - why suffer if it can be fixed quickly?

I've had something simular (although not as painful as yours) for several months, and I too thought it might be caused by bad sleeping position. I've had about 3 sessions of acupuncture now and it's practically (90%) gone.

A course of ibuprofen three times a day for a week wont do you any harm at all and after that you'll know if it's improved or you need the GP to check it out

I've got something similar- but as others said, could be a lot of things. Mine was thought to be a trapped nerve at first, then after an xray, diagnosed as calcification of the tendon, then as a by product of a type III separated a-c. Now considered to be arthritis bought on by trauma due to the aforesaid separated a-c.

If you google shoulder impingment, or supraspinitus tendonitis. I have a crap sleeping position and the pain was at its worst sleeping. When I went for an xray, i was diagnosed with Acute Calcific Supraspinitus Tendonitis. Old injuries apparently from skiing, badminton, volleyball and mountain biking catching up. The pleasures of an active youth. Diclofenac and physio sorted it out. Still have twinges if I wake up and have been sleeping with my hands behind my head.

Hope this helps.

Alan

Mrs Ratadog had a frozen shoulder which proved immune to painkillers and physio. At medical school the teaching was that frozen shoulder was an inflammatory process where the tissue in the joint became inflamed and stuck together and then after a year or so magically healed. Doesn't really hang true as most things that become damaged scar and adhesions are usually permanent.

Did some research and came across Trigger Point Therapy. See[url= http://www.triggerpointbook.com/frozenindex.html ]here[/url]. Book available from Amazon etc. Essentially says that frozen shoulder and some other muscular conditions are caused by tears/malfunctions in the muscle which can be self or partner treated by massaging specific trigger points.

Approached it with a fair amount of scepticism and a dollop of desperation but it seemed to make a significant difference both in the case of the missus and in the case of a work colleague with the same problem.

You need to get a diagnosis because there are other causes of shoulder pain as outlined above, but if it is a frozen shoulder it may be worth an investment in the book.

As an aside, I now find the knowledge gained from wider reading on the subject useful in dealing with knackered muscles after riding which is a double plus.

Only annoying thing is that despite this branch of knowledge being developed by the medical profession with good evidence to support it and being used by certain pain clinics, it seems to be unfashionable in mainstream medicine and not widely known.

I was 'diagnosed' with a frozen shoulder. It turned out after visits to the physio to be a rotator cuff injury. I've been doing the recommended excercises (stretching mainly) and it is much better. Not right yet, but on the mend.

Be careful of snap diagnosis; get the best info you can.