Dislocated Knee Question?

About a year and a half ago, I dislocated my right knee. It was put in a leg stabilizer, i took pain medication, and it apparently has healed wonderfully. I rarely, if ever, have pain or swelling in it. However, I've recently begun a running/walking regimen (1.6 miles, 6 days a week) and I've noticed a lot of pain in my left knee, which I've never had trouble with. I've noticed pain in this knee before, a sharp fleeting pain, but now I'm just worried it's going to give out or get overly stressed and cause serious damage. I've been doing different stretches and strengthening exercises but I'd just like to hear opinions and advice. Has this happened to anyone else? What did you do?