gums are receding but very healthy looking

I brush my teeth twice a day and floss not as often as I should but pretty frequently. My teeth and mouth are always healthy and clean because I can't stand the idea of an unhealthy mouth. My gums aren't red or inflamed. Recently when I brush my teeth there's one part of my gums that hurt and I looked and it seems to be receding there (one of my canines) . Any idea why or what this could be? Thanks