Plantar Fasciitis: This condition is the most common cause of heel pain, especially when it occurs with pressure and walking. It involves inflammation of the plantar fascia, a band of tissue that runs along the bottom of the foot, supporting the arch.

Achilles Tendinitis: Inflammation of the Achilles tendon, which connects the calf muscles to the heel bone, can cause pain in the heel, especially with activity.
Heel Spur: A bony growth on the underside of the heel bone can cause pain when walking or pressing on the heel.
Fat Pad Atrophy: Thinning of the fat pad under the heel can lead to pain, especially with pressure and walking.
Overuse or Repetitive Strain: Activities that involve repetitive running, jumping, or walking can lead to heel pain due to overuse.

Infection (e.g., Osteomyelitis or Septic Arthritis): Although less common, infections in the bone or joint of the heel can be serious and require prompt treatment.
Tumor: Both benign and malignant tumors can occur in the heel, and while rare, they are critical to diagnose early.
Fracture: A stress fracture or other types of fractures in the heel can cause pain, especially with weight-bearing activities.

Rheumatologic Conditions (e.g., Rheumatoid Arthritis, Psoriatic Arthritis): These conditions can cause heel pain among other symptoms, but are less common causes compared to the above diagnoses.
Nerve Entrapment (e.g., Tarsal Tunnel Syndrome): Compression of nerves in the foot can lead to pain, numbness, and other symptoms in the heel and foot.
Bursitis: Inflammation of the bursae (fluid-filled sacs) near the heel can cause pain and swelling.