Sounds like could be plantar fascia.

How often and how much have you been riding (same bike?, same position - on bike and cleats?, same shoes/inserts/socks/no socks?, same trainer?)

---

Two wheels good. Four wheels bad.

My money is on your back. L5-S1 pinch, messed up your calf, yanks on your heel because that's where it attaches.
I had the same thing, fixed easily by a great sports chiro. I'll p.m you his name

---

NO

Nothing different and never had a pain there before. I went and pedaled for a while and there is ZERO discomfort.

It literally only hurts to walk. I can run (forefoot striker), bike, swim, & jump with no discomfort or hint of an issue. I just can't walk.

I know you said it doesn't hurt when you run but have you tried running any distance since you noticed the pain? I've been battling a heel issue for a few months now and although it doesn't bother me too much when I run (or at least it didn't at first), a few hours after or even the next day it blows up.

FWIW, my issue is a mix of peroneal tendinitis, Achilles tendinitis, PF, possibly bursitis and a few other things thrown in the mix. The pain can be anywhere from right on the ball of my heel, to the outside, to just in front of the plantar fascia insertion. It sucks. If it continues for more than a couple days I'd get it looked at. I ignored mine for a while and I'm paying the price now.

Big caveat to what I'm about to say here, and that is that you are going to get a bunch of armchair quarterbacks weighing in here, including me.

I'd say tinker with the positioning of your cleat. Or perhaps your shoes are getting old? Any time I have foot issues with my cycling, it is because of an issue with the shoe/cleat/pedal contact.

If it's on your actual heel pad then it could be the Heel Fat Pad Syndrome. I have a similar issue and thought it was PF but Dr. says otherwise. Other than taking a few weeks off completely or putting me in a boot he suggested using some PF type insoles and/or heel cups. It helps a little but doesn't treat the issue. Sucks either way and time off is probably the right answer.

---

Instagram or twitter me softly @xatefrogg