@ckomis, It sounds like your transplanted kidney is doing well, but your quality of living has been affected as you have indicated by the sob that you are experiencing.
I didn't have a fistula. I have a transplanted kidney and liver and I don't know if this pertains to your situation. I saw the sob (shortness of breath) with exertion and wanted to share what I experienced. I had been taking prednisone along with my other anti rejection meds for several years at a low dose. However after I was tapered off the prednisone, I began to experience sob. For me it was really noticable when I couldn't catch my breath on the walking path or when hiking. I was eventually diagnosed with a exercise induced asthma that became active after getting off prednisone.

What has your transplant team suggested about removing the fistula if it is the suspect cause?