I’ve never experience the runner’s high, endorphine-flooded, goofy-this-feels-like-walking-only-faster-I-could-run-forever state of being. I feel every foot-pouding step, every muscle contraction, every oxygen-drenched breath when I run. I run for two reasons: 1. The sense of accomplishment is addicting. 2. To tell myself, “no.” When I completed my first 5K, I was totally pumped. Not by runner’s…