Doesn't matter if it's after a completely sedentary day, or a Saturday after playing a couple hours of pickup ball. But the back of my ankle pops pretty often, probably 5/6 times a day. It's always right at the base of my Achilles', I know it's not the tendon because tendons don't do that and certainly not painlessly. There's absolutely no pain at all, and it's not like popping your knuckles where you feel a pressure release, it's just a loud CRACK. No pain before, during, or after. It happens in both ankles but probably 80% of the time it's in my left one. It's been happening for probably 6/7 months.

Anyone ever had this? Know a possible reason? Is it a cause for concern?