Muscle tears and PMR and/or pred?

Hi. I was diagnosed May and since that time I have tried to learn how to manage this bleedin' disease. My rheumy told to take 20 mg. for I think it was 3 or 4 weeks. Then things improved so she said I could go to b 15 mg for 2 weeks and then down to 10. Well things did not go well. She has been booked so I am doing my own thing. I did 20 again then 16 for weeks but symptoms would just hang on. Then I tried 17.25., finally 3 days ago I went to 20 again. It's helping some but I don't think enough. Today ended up being a very painful day. I might go up a few more mgs.
So this is my question...last week I was doing something minor And moved my arm and felt seering pain in my bicep. I could hear and feel something rip. I saw stars. Then two days ago I leaned down to pick something off the floor and same thing happened in the back of my left thigh talk about painful!!..today I went out on the porch with dog and.damn I took a step and once again felt that same thigh muscle kind of rip again. I was so mad. Ever since I was sent on a fast.pred reduction I have been in so much pain and so exhausted that I am not doing much. So have any of you experienced this? I know pred is hard on your body...and so is PMR... Duh! But .... I take.magnesium everyday and have do so for.more than a year. I take a multi vitamin as well. So...any experience, ideas, treatments...pls let me know. Also anyone heard of MSM? And last...I am thinking of increasing fr 20 for a bit to see if I can get more than two decent hours in a day....not including my muscle rip days. Thanks everyone.