The tendon pain inside the left buttock should be rested and treated adequately, and can be done in a flat supine position to be able to relax the hip joint. It is also able to reduce the pressure on the sacroiliac joint and lumbar spine, thus preventing the symptoms of tendon pain inside the left buttock caused by lesions of the sacroiliac joint or lumbar spine. Patients with particularly severe pain can take oral diclofenac sodium extended-release capsules, which have a very obvious effect on pain, and the use of loxoprofen sodium extended-release capsules and ibuprofen extended-release capsules can have a similar effect, relieving pain while also reducing the possible local soft tissue inflammation. It is best to combine this with oral horse chestnut seed extract tablets, which can enhance the pain relief. After the above treatment, if the symptoms are not relieved for more than 3 days, you should promptly visit a regular hospital. CT or MRI of the lumbar spine, sacroiliac joints and hip joints should be examined to further confirm the diagnosis of the disease.