Chondromalacia

Hiya, been battling with chondro in my R knee since I was 19 yo (i’m now 26) I haven’t been doing any serious running in maybe a year due to the pain ever since I did the philly half marathon last. I signed up for the Full thinking I gave my knee enough time to heal, but it still hurts once I’ve gotten past maybe 4 miles? My pace is only 11-12 mins. Any stretches, exercises, or ways I can tape up my knee to help support it?