What's the difference between heel fat pad syndrome and plantar fasciitis?

Heel pain has more than one source, and the names can blur together. This page lays out what plantar fasciitis looks like so you can hold your own symptoms up against it.
The short answer: start with what plantar fasciitis feels like
Cleveland Clinic describes plantar fasciitis as a weakening of the connective tissue (the fascia) that supports the arch of your foot. Your plantar fascia stretches from your heel to your toes.
The signs it lists
Cleveland Clinic says the main symptom of plantar fasciitis is a throbbing pain in your heel. It adds that the pain is usually closer to your instep or inner part of your heel and may extend to your foot's arch.
You may also feel a tightness in the bottom of your foot when stretching, according to the same source.
How to compare your own heel pain
Pin down where it hurts and when. Is it near the inner part of the heel, does it reach the arch, and does stretching tighten the sole? If your answers match the list, plantar fasciitis is a fair question to raise. If they do not, tell your clinician exactly where the pain sits.
For further reading, a page on plantar fasciitis, a page on plantar fasciitis and bone spurs and a general guide to foot injuries and disorders are useful. A physical therapy guide to plantar fasciitis is also available.
The standard: location is the clue
A pain map is a useful tool to keep at home. Before a visit in Elmwood Park, mark the exact spot on your heel and note what triggers it. That detail helps a clinician separate one heel problem from another.