Asymmetrical pain in heel bone

About 2-3 months ago, I detected a mild-to-medium intensity pain that feels to be mostly inside and to a lesser extent around my RIGHT heel bone. The pain is accompanied by a tightness of the Achilles tendon and is present regardless of whether I am walking, sitting, or lying in bed. The pain is not constant, but intermittent in time and duration, one that, nonetheless, thus far I have not been able to associate with any other condition. I am a 73 years old male, somewhat overweight (working on it with slow success), but otherwise rather healthy. Except for some vitamin supplements and ever greater attention to nutritious eating, I take no medication of any kind. Again, aside from the fact that it is only in my right foot, I am not particularly discomfited by the pain. Indeed, when doing exercise, including plain walking or on the treadmill, the pain seems either to be gone or it may just be overridden by the effect of the exercise itself. Moreover, I also keep wondering whether it is a symptom of something else happening in my body. I have not consulted any physician so far but am considering doing so if the pain does not disappear – as sometimes pains in various parts of the body have been known to do. Nonetheless, I find this pain baffling -- why only the right foot -- as well as irritating, and am determined to eliminate it one way or another.