I have severe pain in my left hip-back area and downleft leg to knee.

I always suspect back issues, causing referred pain, when people post these sorts of pains as that is apparently what caused me years of sciatica.  I thought I'd need a hip replacement but it turns out my hips are about my only body parts which don't have any sign of OA!  Various physiotherapy treatments and exercises I do at home have sorted this out for me.  Pred did make the pain go away when I was at my initial highest dose, but it came back as I was reducing.  But now I have none, or only very rarely and there's usually a reason.

Forty-niner, I get PMR pain on both sides, but primarily on the right side. Both in the groin and shoulder most people are affected the same on both sides. Does increasing Pred have any effect? Good luck!

My pain is always worse on one side than the other and I do know others with PMR who say  it is that way for them also. Everyone is different, we all experience it in our own way. But of course there's always a possibility of other problems occurring at the same time as the PMR. 

Much more likely to be myofascial pain syndrome or something else rather than "just" PMR. Piriformis syndrome is also a possibility. Both can pinch the sciatic nerve and cause sciatica.

I have left hip pain going down the outside of my leg to my knee and halfway down to my ankle.   Physio says it is Iliotibial Band Syndrome.    It is much relieved by his treatment and the hydrotherapy I am having for my increased pain since reducing to 6.5 mg.   He thinks the general weakness in my muscles is to blame.   Hopefully the hydrotherapy will strengthen the muscles.    Good luck !