It's a shame I can't run in front of a mirror, because I would have figured this out ages ago.
My trouble has always been with my left lower body (foot, ankle, calf, knee, quad). Every injury I've had, from when I sprained my ankle at age 11 to this recent knee problem, has been on the left. Meanwhile, I've had other aches and pains in the upper half of my body on the right side (ab soreness, shoulder strain, etc.) but never the right.
I joked before that I thought this had to be the handiwork of someone who had created a voo-doo doll of me and was sticking needs only on the left side. But I have discovered a more likely culprit: I overwork my left side when I work out, and then afterwards carry things (my laptop, purse, children, lunch, sometimes all at once) with my right side perhaps because my left side has already had enough.