I Apparently Have Plantar Fasciitis On My Left Foot. I

I apparently have plantar fasciitis on my left foot. I am not an athlete, tho do walk on a treadmill recently quite regularly. Will I cause permanent damage if I continue doing so with my heal? I have started using inserts which help to a point. I am 48 years old and in the process of losing weight. I would really rather not have to stop my cardio...are there any easy fixes for this?
Thank you.