PB, thanks for your response!

Thank you for the new hypothesis that I wasn't aware of: hypersensitivity of the coccyx.

Thank you the explanation of the possible causality of this thing, probably by long time sitting patterns.

Thank you for addressing "prognosis", which is that this thing takes a loooong time to go away.

I've finally found a physiotherapist in my area "with 25 years of clinical experience and particular expertise in the management of hip, groin and lumbo-pelvic pain and dysfunction" (from website). I will mention to look for pelvic asymmetries. I expect there will be an overall pelvic musculoskeletal assessment and overall pelvic musculoskeletal fitness recommendations. I have to wait another six weeks before this appointment.

If I could ask one question, it would be: is there any stretch, mobilisation movement, trigger point therapy, or strengthening exercise that I could do at home as part of my fitness routine. Even if we can't be exactly sure of what will help, I'd welcome to know the types of things that often may help. If you give me a name of something, I will websearch it to get a more detailed description of how to do it. By the way, I am now doing glute trigger point therapy as part of my fitness routine, as recommended by my personal trainer, which sitting on a large trigger point ball starting with "outer, upper back pocket area" and then to middle side of glute. I am finding significant tension in these glute areas.

Frankie