Pain at the back of your foot while walking usually comes from one of three closely related problems: inflammation of the Achilles tendon, irritation of a fluid-filled cushion near your heel bone, or a bony bump that develops where the tendon meets the bone. These conditions share the same neighborhood of anatomy, and it’s common to have more than one at the same time. Understanding which one is driving your pain helps you treat it effectively.
The Three Most Common Causes
The back of your heel is a tight, busy intersection. Your Achilles tendon, the thick band connecting your calf muscles to your heel bone, does heavy work every time you push off the ground. Tucked between that tendon and the bone sits a small fluid-filled sac called a bursa, which reduces friction. And the bone itself can develop an enlarged ridge right at the attachment point. When any of these structures gets irritated, you feel it with every step.
Orthopedic specialists sometimes call the combination of all three problems the “terrible triad” of posterior heel pain: Achilles tendinitis, retrocalcaneal bursitis, and Haglund’s deformity occurring together. They feed into each other. A bony bump irritates the bursa, the swollen bursa presses on the tendon, and the inflamed tendon pulls harder on the bone. That’s why back-of-the-heel pain can feel like it’s getting worse over weeks or months if you don’t address it.
Achilles Tendinitis
This is the most common culprit. Repeated strain on the Achilles tendon causes tiny areas of damage that the body can’t repair fast enough, leading to pain, stiffness, and sometimes mild swelling along the back of the heel or just above it. The pain is typically worst when you first start moving after rest, like your first steps in the morning or standing up after sitting for a long time. It may ease once you warm up, then return after prolonged activity.
Several factors raise your risk. Flat feet and high arches both increase strain on the tendon by changing how force travels through your foot. Tight calf muscles do the same thing. Carrying extra weight adds load with every step. Walking or running on hills puts the tendon through a greater range of motion under stress, which can push it past its tolerance. Even a sudden increase in how much you walk, like a vacation with long sightseeing days, can trigger it.
Heel Bursitis
The bursa between your heel bone and Achilles tendon can swell and become painful on its own, though it often shows up alongside tendon problems. Retrocalcaneal bursitis tends to produce pain and swelling that’s slightly deeper than tendinitis, nestled right where the tendon meets the bone. You might notice warmth around the heel, skin color changes, and pain that gets significantly worse when you stand on your toes or push off while walking.
A less common type, subcutaneous calcaneal bursitis, involves a different bursa that sits between the skin and the tendon. This one is more directly aggravated by shoe pressure. Both types can make the back of the heel look puffy or swollen compared to the other foot.
Haglund’s Deformity
Sometimes the problem is structural. Haglund’s deformity is a bony growth on the back of the heel bone that you can see and feel as a visible bump through the skin. The bump itself isn’t always painful, but shoes that press against it create friction, swelling, and irritation of the surrounding soft tissues. Over time, that chronic pressure can trigger both Achilles tendinitis and bursitis, which is how many people end up with the terrible triad.
If you notice a hard bump on the back of your heel that gets red and sore in certain shoes but feels better in open-backed sandals or when barefoot, Haglund’s deformity is a strong possibility.
Less Likely but Worth Knowing
Plantar fasciitis is one of the most common foot conditions overall, but it causes a stabbing pain on the bottom of the foot near the heel, not the back. If your pain is clearly behind the heel rather than underneath it, plantar fasciitis is unlikely to be the main issue, though some people have both conditions at once.
In children and teens, back-of-the-heel pain during activity is often a growth plate issue. Girls between 8 and 13 and boys between 10 and 15 are in the prime window. The heel bone’s growth plate hasn’t fully hardened yet, and repetitive impact from sports can irritate it. A doctor typically diagnoses this by squeezing the heel at different points to locate the tenderness, sometimes with an X-ray to rule out a fracture.
How Your Shoes Make It Worse
Footwear plays a bigger role in posterior heel pain than most people realize. The “heel drop” of a shoe, the height difference between the heel and the toe, directly affects how much stress lands on your Achilles tendon and heel. A lower drop shoe (closer to flat) puts more strain on the foot, ankle, and lower leg. A higher drop shoe elevates the heel, which helps absorb impact and reduces tension on the calf and Achilles complex.
If you’ve been walking in flat shoes, minimalist sneakers, or worn-out footwear with compressed cushioning, switching to shoes with more heel elevation and firm arch support can reduce the pull on your Achilles tendon noticeably. Rigid heel counters (the stiff cup at the back of the shoe) can also press directly on a Haglund’s bump or inflamed bursa, so look for shoes with softer or padded heel collars if you have swelling or a visible bump.
What You Can Do About It
Most posterior heel pain responds well to conservative treatment, but it takes patience. The standard rehab exercise for Achilles tendinitis is the eccentric heel drop: you stand on the edge of a step, rise up on your toes, then slowly lower your heels below the step level. The typical protocol is 3 sets of 15 repetitions, twice a day, every day, for 12 weeks. That timeline surprises a lot of people, but tendon tissue heals slowly because it has limited blood supply. Consistency matters more than intensity.
Beyond the exercises, a few practical changes help. Ice the back of your heel for 15 to 20 minutes after activity to manage inflammation. Stretch your calves gently throughout the day, especially before walking. Avoid going barefoot on hard surfaces, which forces the Achilles to work through its full range without any cushioning support. If certain shoes aggravate the pain, switch to ones with a padded heel collar and good arch support, or use a small heel lift insert to reduce tendon strain.
Signs That Need Urgent Attention
Most back-of-the-heel pain is a nuisance, not an emergency. But one scenario requires immediate medical attention: a sudden, sharp pain at the back of the heel or calf accompanied by a popping sound. This can signal an Achilles tendon rupture, a partial or complete tear that typically makes it very difficult to push off with the affected foot. If you hear or feel a pop followed by sudden pain and weakness, that needs same-day evaluation. A rupture often requires different treatment than tendinitis, and outcomes are better with early intervention.
Pain that steadily worsens over weeks despite rest, or swelling that doesn’t go down, also warrants professional assessment. An MRI can distinguish between tendon damage, bursitis, and bone problems, which helps target treatment to the actual source rather than guessing.