I can relate to what you are experiencing, however my gut symptoms preceded the PMR by decades. About 6 months ago we discovered that my 40yr old son and his 7 yr old son had Celiac disease. It is an inhereted disease that destroys the lining of the small intestine, much more common than previously thought and most Doctors do not test for it. The blood test for antibodies to gluten is ineffective if you have been on Prednisone or other immunosuppressive meds. The only way to find out for sure if you have it is endoscope biopsy of the small intestine taking several samples. However if you go 100% gluten free and your symptoms resolve within a month or so, you can be fairly confident this is the root cause of your gut issues and probably the PMR as well. I have had a very significant decrease in my PMR pains since going 100% GF 6 months ago, down to 1mg Prednisone after an 18 mth struggle . It's not an easy process especially living in a house with others who are not on GF diets but definitely worth the trouble.