The cause of Achilles tendon pain after waking up in the morning is usually to exclude Achilles tendonitis, which is a sterile inflammation of the Achilles tendon after acute and chronic injury, mostly in patients who love running and jumping sports all year round. The cause of Achilles tendonitis is usually related to the patient’s lack of activity and preparation, and it is not excluded that the patient has a degree of infection near the Achilles tendon, or for patients with flat feet, it is also easy to complicate Achilles tendonitis. Inappropriate shoes and excessive exercise are the causes of Achilles tendonitis, mainly manifested in soreness and pain above the heel, which may not be obvious with proper exercise during the day, but after a long rest period at night, the local inflammation is manifested as increased pain in the morning when getting out of bed.