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6 Signs Your Achilles Pain Is Actually Tendonitis

August 17, 2026

One day your heel feels a little tight when you get out of bed. A few weeks later, you’re avoiding the stairs, cutting walks short or wondering why your it hurts every time you stand up.

“Many people assume Achilles problems only affect runners and athletes, but we see it in people of all activity levels,” says Thomas McDonald, MD, with Hartford HealthCare’s Bone & Joint Institute. “The Achilles tendon handles an enormous amount of force every day, whether you’re exercising, climbing stairs, walking the dog or simply moving through your normal routine.”

But recognizing the early signs of tendonitis can help keep a minor irritation from becoming a much bigger problem.

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1. The pain is right where your tendon meets your heel

Let’s start with the obvious question: Where does it hurt?

The Achilles tendon is the thick band of tissue connecting your calf muscles to your heel bone. When it becomes irritated, pain typically develops somewhere along the back of the ankle or lower leg.

And the location of that pain can offer important clues.

“Pain at the back of your heel is different from pain on the bottom of your foot, which may suggest conditions like plantar fasciitis,” Dr. McDonald adds. “Understanding exactly where your symptoms occur helps us narrow down the cause.”

2. Your first few steps in the morning are the worst

This is one of the easiest clues to miss.

You wake up, swing your legs out of bed and immediately notice stiffness or soreness in the back of your ankle. But after walking around for a few minutes, it starts to loosen up.

“Because the tendon tightens while you’re resting, morning stiffness is extremely common,” says Dr. McDonald. “That makes those first few steps very uncomfortable.”

3. It gets worse after activity

This can be misleading, because you might feel fine during activity. But after? That’s when the discomfort kicks in.

“Patients are often surprised that symptoms don’t always appear immediately,” says Dr. McDonald. “Your Achilles may seem fine in the moment, but become sore hours later or the next day.”

This can make it difficult to connect the Achilles pain to a specific activity.

“Sometimes the culprit isn’t a major event,” Dr. McDonald adds. “It may simply be an increase in walking, yard work, pickleball, hiking or another activity that places additional stress on the tendon.”

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4. Your Achilles feels swollen or warm

Achilles tendonitis isn’t only about pain.

Sometimes you’ll notice physical changes in the tendon itself. It may appear slightly swollen, feel thicker than normal or become tender when touched.

“When inflammation develops, your Achilles can become enlarged or sensitive,” says Dr. McDonald.

And because these changes are gradual, they can be harder to spot.

“Your Achilles isn’t going to become irritated overnight,” Dr. McDonald says. “Symptoms develop over weeks or months as repetitive stress builds up.”

5. Going up stairs suddenly feels harder

Every time you push off the ground, your Achilles is under pressure.

That means climbing stairs, walking uphill or standing on your tiptoes may become challenging if you have tendonitis.

“You may notice symptoms during movements that require calf strength, like climbing stairs or pushing off when you’re walking,” says Dr. McDonald.

Even simple activities can become frustrating.

“If you’re having to avoid certain movements because of pain, that’s a sign something is wrong,” Dr. McDonald adds. “Discomfort should never be what’s limiting your physical activity.”

6. The pain keeps coming back, even after a break

Sure, a few days off seems to help. But if the pain in your Achilles keeps coming back as soon as you return to activity? That’s a red flag.

“Temporary improvement doesn’t mean the underlying issue has resolved,” says Dr. McDonald. “You may feel better because the stress has been removed, but tendonitis likely needs rehabilitation to fully recover.”

That’s why repeated flare-ups deserve attention.

When to see a doctor

Every minor ache shouldn’t send you rushing to a doctor. But persistent pain should never be ignored.

“The sooner we address Achilles tendon issues, the more options we typically have for treatment,” says Dr. McDonald. “If the condition is caught early, you’re more likely to improve with activity modifications, physical therapy or targeted rehabilitation.”

And there’s one symptom you should never ignore.

“If you feel a sudden pop, combined with severe pain or difficulty pushing off your foot, seek medical attention right away,” Dr. McDonald says. “Those symptoms can sometimes indicate an Achilles tendon rupture, which is a very different injury.”