You have a muscle called the Piriformis that attaches to the top of the femur and the sacrum which can shorten iif it goes into spasm and feels like sciatica
Try lying on your back, with knees bent, grasp one knee and draw towards your chest then slide other heel until leg is straight and hold for maybe a count of ten but whatever you can manage. Repeat on the other side

Me too suffers from buttock pain, hip pain and Some part of the groin. Sometimes, I find it hard to sit on hard surfaces. Pain on my hips wakes me up at night too.

Have you try MMJ edibles ?

I also get the pain that starts in my buttock and runs down the back of my leg. It is very painful. I have tried stretching and all sorts of things and nothing has been very effective.

I get sore wrists and fingers...tendinitis and arthritis.Emu oil helps.