Heel spurs are often blamed by the general public for most heel pain. In actuality, spurs rarely ever cause pain in the bottom of the heel.
The reason for this is related to the shape and orientation of the spur on the bottom of the foot, as opposed to spurs on the back of the heel (which can cause pain). A spur on the bottom of the heel usually develops as a response to traction, or pulling, on the heel bone by arch tissue attached to the front part of the bottom of the heel bone. This tissue is usually always the plantar fascia, which stretches away from the heel bone as the foot flattens. When the flattening is excessive, the tugging of the fascia stimulates the outer layer of the bone to create more bone. Over time, this bone formation results in a long extension away from the bottom of the heel bone, but parallel to the ground. The shock generated in high arched feet can also generate this reaction, but this is far less common. The reason these spurs do not result in actual pain is that they a re positioned parallel to the ground, so one is walking WITH the spur, and NOT on TOP of it. Since the spur is not digging into the heel pad tissue, it essentially becomes an extension in the length of the bottom of the heel bone. The pain therefore comes from the inflammation in the tissue that stimulated the bone growth, namely the plantar fascia. It is also not uncommon for someone to have a heel spur incidentally noted on an x-ray for some other condition, and never have ever experienced heel pain. This is because the traction that produced the spur, namely the strain of the plantar fascia, does not always result in inflammation that turns into plantar fasciitis. Some people can go their entire lives with heel spurs and not have a day of heel pain.
There is an exception to the above explanation. Some conditions that affect joints, namely the autoimmune arthritic diseases (like rheumatoid arthritis), can produce small fluffy spurs that face towards the bottom of the heel bone tissue into the soft tissue on the bottom of the heel. By nature, these fluffy spur reactions are already inflamed, and their presence into the bottom of the heel causes inflammation of the tissue under the heel bone. These spurs are independent of the fascia, and are painful in and of themselves.