I Had Kidney And Pancreas Transplant In February 2016. I

I had kidney and pancreas transplant in February 2016. I am now having pain in the muscle of my left leg from half way my thigh down to half way my calf. Poor circulation has been ruled out. The ache and become weak if I don't stop walking for a few minutes. Does anything come to mind of what this may be and how I can treat it?