Heel pain is often worst first thing in the morning due to the overnight inactivity, which allows the muscles and tendons in the foot to tighten, especially the plantar fascia and the Achilles tendon. These tissues connect to the heel bone and are typically under a lot of stress during the day from walking or standing.

When you sleep, your feet are generally in a relaxed position and the fascia and other tendons slightly contract and cool down. Upon waking and taking the first few steps, these tissues suddenly stretch back to their functional length, which can cause micro tears or strain at the point where they attach to the heel bone, resulting in sharp, intense pain. This phenomenon is especially prevalent in conditions such as plantar fasciitis and Achilles tendonitis, and the pain usually decreases after the tissues stretch and warm up with continued movement.

Heel pain can be caused by numerous factors including overuse injuries, inflammatory conditions such as plantar fasciitis or Achilles tendonitis, structural issues like flat feet or high arches, or even systemic diseases like arthritis. It can also occur from wearing poorly fitting or inappropriate footwear for certain activities.

Plantar fasciitis typically causes a sharp, stabbing pain at the bottom of the foot near the heel. This pain is usually most intense with the first steps in the morning or after a long period of sitting. If your heel pain matches this description, it might be plantar fasciitis, but a clinical evaluation can provide a definite diagnosis.