A heel spur is an abnormal growth of the heel bone, which causes pain. Plantar fasciitis, on the other hand, is an irritation of the fascia of the sole of the foot due to various causes. The latter causes micro ruptures over time that calcify and lead to bone spurs.
Not in all cases of plantar fasciitis is a calcaneal spur evident. Of course, they are linked pathologies that have similar symptomatologies and treatments. However, it is the abnormality in the fascia that causes this kind of painful calcification.