The most common causes of Achilles tendon pain after running are Achilles tendon strain, Achilles tendonitis and bone spur. 1. Achilles tendon strain: If you have been running for a long time and strenuously, it is easy to cause Achilles tendon strain, and then pain in Achilles tendon will occur. 2. Achilles tendonitis: Trauma to the Achilles tendon and repeated pulling and wearing of the Achilles tendon will easily lead to aseptic inflammation of the Achilles tendon, resulting in pain in the Achilles tendon, which usually requires sufficient rest and elimination of the aseptic inflammation through medication. 3. Bone spurs: due to trauma or strain and other factors, it is easy to cause bone spurs in the Achilles tendon, which may stimulate the Achilles tendon stop when running, and produce pain and aggravate the symptoms. There are many reasons for Achilles tendon pain after running, and it may also be related to osteoporosis, etc. If the symptoms do not improve after resting, it is recommended to go to the hospital in time to find out the cause of the disease and carry out targeted treatment.