Conditions that cause heel pain generally fall into two main categories: pain beneath the heel and pain behind the heel.

Pain Beneath the Heel

If it hurts under your heel, you may have one or more conditions that inflame the tissues on the bottom of your foot:

Plantar Fasciitis

One of the most common causes of heel pain is plantar fasciitis. This is caused due to the inflammation of the band of tissue connecting the heel bone to the toes. Pain due to plantar fasciitis can be felt in the heel or the arch and is usually worst in the morning. The first step coming out of bed is usually the most painful one. Common causes of plantar fasciitis include a high level of physical activity; standing for prolonged periods on concrete or hard surfaces; faulty foot mechanics like flat-feet; tight calf muscles; increased weight; and improper footwear. It is a condition commonly seen in distance runners but is also extremely common in the general population.

Heel Spur

When plantar fasciitis continues for a long time, a heel spur (calcium deposit) may form where the fascia tissue band connects to your heel bone. Having a heel spur may not cause pain and should usually not be operated.

Stone Bruise

When you step on a hard object such as a rock or stone, you can bruise the fat pad on the underside of your heel. It may or may not look discolored. The pain goes away gradually with rest.

Pain In the Heel

If you have pain behind your heel, this may be due to the inflammation of the area where the Achilles tendon meets the heel bone. This may happen due to too much running or wearing shoes that rub the heel too much. Such pain typically builds slowly over time, and the skin becomes thick, red and swollen, in this process.

Retrocalcaneal Bursitis

The bursa acts as a lubricant when muscles/tendons slide over bones. Bursas exist around most large joints of the body, including the ankle.
The bursa located at the back of the ankle, by the heel, is called retrocalcaneal bursa. Repeated/excessive use of the ankle may cause the bursa to get inflamed, leading to this condition called retrocalcaneal bursitis.

The most common symptoms of retrocalcaneal bursitis include:

• Pain in the heel, especially with walking, running, or on touching the heel
• Increased pain when standing on tiptoes
• Red, warm skin over the back of the heel

Achilles Tendonitis

Achilles tendon connects the calf muscle to the heel. This tendon is used for walking, running and jumping. Achilles tendonitis is a condition in which this tendon gets inflamed due to over use of the foot. This condition is most common in people below 35 years of age and often occurs in runners and other athletes.

Symptoms include pain in the heel and along the length of the tendon when walking or running. The tendon may be painful to touch or move. The area may become swollen, and you may have trouble standing up on one toe.

 Achilles tendonitis is more likely to occur in cases of:

• Sudden increase in activity
• Running on hard surfaces
• Excessive running
• Excessive jumping (for example, when playing basketball)
• Wearing improper shoes 

Ankle Sprains

An ankle sprain is an injury to the bands of ligaments that surround and connect the bones of the leg to the foot. The injury typically happens when you accidentally twist or turn your ankle in an awkward way. This can stretch or tear the ligaments that hold your ankle bones and joints together.

Rheumatoid Arthritis (RA)

RA is a chronic disease of the joints that occurs when the body’s immune system mistakenly attacks the synovium, the thin membrane that lines the joints. The result can be joint damage, pain, swelling, inflammation, loss of function and disability. In about 90% patients with rheumatoid arthritis, the joints of the feet are ankles are affected.

Gout

Gout is a form of arthritis that occurs when excess uric acid, a bodily waste product circulating in the bloodstream, is deposited as needle-shaped monosodium urate crystals in tissues of the body, including the joints. For many people, the first symptom of gout is excruciating pain and swelling in the big toe – often following a trauma, such as an illness or injury. Subsequent attacks may occur off and on in other joints, including the ankles. After years with the disease, lumps of uric acid, called tophi, may form beneath the skin around the ankles.