I don't know for beans about tarsal tunnel (and don't want to either -- PF is more than enough for me to manage, and often has been TOO much). But -- I do know that I had many classic symptoms of PF (morning pain, direct heel pain, pain upon rising after resting, relief from moderate icing, etc.) and I always figured that the constant aching and throbbing was part of it. I was bona fide officially diagnozed by two docs, one a podiatrist and one an orthopedic surgeon, plus with all the regular symptoms I had, PF seems to be a natural.
(Fortunately I am a lot better now so I don't have that constant throbbing -- a fact for which I give thanks every day. But, I know what it's like and it's horrible.) Hope you get the PF or TTS issues resolved for yourself soon. Meanwhile, I wouldn't presume that the throbbing and aching is NOT a symptoms of PF. It may not be the most classic, but I'll bet it's very common.