Sounds interesting.

What treatment have you had - precisely if possible.

Does the stretching help?

Has someone assessed your Wikipedia reference-linkSIJ using the Gillet / Stork test? Results?

Does it hurt to cough or sneeze - in particular pain in the ribs?

How did the physio decide you have an unstable Left SIJ?

Is your SIJ now stable?

How is your "scar tissue" that you have been rubbing?

In general, would you say you are a motivated-type of person or are you really laid back?

How do you know the right psoas is tight? Did they do a Thomas test? Is it tight or overactive?

Same with hamstrings - are they tight or overactive?

Have you had a CT scan?

You may not be able to answer all these questions but i think they would be helpful for us.

Lastly, this has obviously been going on for some time. The "pain" can often be made worse by chemical changes in the brain - this is a really cutting edge side of the research coming out about persistent pain (often called chronic pain).

Hang in there and we will lick this thing!