I have myopathy from prolonged high steriod use from sudden sudden onset of asthma. I developed secondary Addison's Disease from the steriod use. My myopathy affects all four extremities but my left side is worse than my right. I have to wear a brace on my left foot due to the severe weakness there. If you don't find you have a muscle disease, I was tested for that too, try an endocrinologist and have them check your am cortisol levels. Good luck and feel free to contact me.