Overstressing the Achilles tendon due to increased walking or running, increased weight, and excessive chest tightness of the calf muscles can all put additional stress on the tendon. Shoes that are unstable and give no support, badly worn-down heels, and changes in heel height to low or flat heels also place extra stress on the Achilles tendon.

Biomechanical factors, such as excessive pronation, are common in patients with Achilles tendinitis or tendinosis. The mechanism of injury is when prolonged pronation and subsequent leg rotation cause a torque or twist in the tendon.

Achilles tendinitis, also known as Achilles tendinopathy, is usually noticed as a gradual development of pain and stiffness immediately on rising in the morning, which diminishes after walking or following a warm-up before or during exercise, only to recur afterward, often with a burning sensation. There is localized thickening of the tendon with swelling of the surrounding tissue that will be tender to touch. Achilles tendinitis can be classified as acute or chronic, where symptoms have been present for over six weeks.  Acute tendinitis usually occurs because of too much exercise too soon.

Tendinosis is not uncommon and is typically diagnosed with an ultrasound examination. Small, discrete degenerative lesions can be found within the tendon, sometimes due to long-standing Achilles tendinitis or degenerative changes associated with aging. Calcification can occur within these degenerative areas, particularly when the tendon joins the heel. Tendinosis can also be asymptomatic, which can predispose to partial tears and even complete ruptures of the Achilles tendon.

There are also two bursas present in the back of the heel. A superficial bursa can become inflamed from rubbing on your shoes, and another deep to the Achilles tendon can become inflamed if it is compressed onto the heel bone, which, if inflamed, may also produce symptoms.

Tendons have a low metabolic rate, which is why they can be slow to heal once injured. Acute Achilles tendon pain responds well to treatment if it is begun at an early stage. If symptoms are allowed to continue, treatment and rehabilitation can take many months.

Reduce load

Treatment is to first reduce the load on the tendon with a reduction in activity to a point where the tendon is asymptotic.  Ice and anti-inflammatory drugs or gels following activity and massage will help reduce pain and inflammation. Heel raises in the initial stages help reduce stress on the Achilles tendon.

Correct the cause

The second aspect of treatment is correcting predisposing factors. A graduated stretching and strengthening program, along with a gradual increase in activity level, is the mainstay of treatment and prevention of reoccurring tendon injuries.

Other treatment modalities that can be used depending on the cause of the pain in the back of your heel can also include

Shoes and orthotics

Footwear and orthoses that correct overpronation directly and positively affect treating and preventing the re-occurrence of Achilles tendon injuries where a biomechanical problem exists.

Moonboot

For partial tears or ruptures, a Moon Boot with a heel lift allows guarded weight bearing while reducing any load on the Achilles tendon. This rests the tendon and allows healing before starting a strengthening program.

Steroid injection

Corticosteroid injection into an inflamed bursa, along with heel lifts, is very effective in reducing pain. It is sometimes used when the tendon sheath is inflamed, but it needs to be carefully considered as it can predispose to tendon ruptures.

Extracorporeal Shockwave Therapy

Extracorporeal Shockwave Therapy (ECWST) benefits chronic Achilles tendon pain, particularly when the tendon joins onto the bone and has not been responding to other treatments. It is typically not used for acute Achilles tendon pain.

Dry Needling

Dry needling has been used to help alleviate pain and is an adjustive treatment, particularly if calf pain is also associated with your heel pain.

Surgery

A patient with chronic Achilles tendonitis that has developed into tendinosis that is not responding to treatment may need surgery to remove the degenerative areas and spurs that can form on the back of the heel. Surgery is always the last option and best avoided if possible, as it does take a long time to recover.