Pain behind and under heel. also feels like fire in heel at times. can feel pulse in heel without touch. calf tightness too. plantar fasciitis?

Heel pain: Plantar fasciitis is a misleading term as this type of heel pain is not inflammatory but rather degenerative in nature. A better term for this would be plantar fasciopathy. It can also be a stress fracture, calcaneal edema, nerve entrapment, tumor, foreign object or a partial tare, etc. Most commonly it would be the plantar fasciopathy. Your local podiatrist can help.

Very likely: Plantar fasciitis is most commonly described as pain under the heel which occurs on first step in the morning or after sitting. However, you should get an evaluation by your local Podiatrist to confirm the diagnosis as other pathologies in the heel can cause pain.