The common causes of hidden pain in one hip include sports injury, trauma, necrosis of the femoral head, synovitis of the hip joint, ankylosing spondylitis, and so on. 1. Sports injuries: Lactic acid buildup due to excessive exercise or muscle strain due to improper exercise posture can lead to vague pain in the hip. 2. Trauma: Trauma can lead to soft tissue injury in the hip and cause hip pain. When the trauma is not very serious and does not involve major blood vessels, nerves and bone fractures, the pain may not be obvious, and only manifests as hidden pain. 3. Necrosis of femoral head: often due to trauma, alcoholism, long-term use of hormones and other reasons, resulting in femoral head blood vessel occlusion, fracture, causing ischemic necrosis of the femoral head, resulting in hip pain. 4. Hip synovitis: aseptic inflammation that occurs in the hip joint, often triggered by overexertion or trauma, causing pain in the hip joint due to the stimulation of inflammatory factors. 5. Ankylosing spondylitis: a chronic inflammatory disease that occurs in the human body, mostly associated with genetics, infections and other factors, which can cause damage to the hip joint tissues and cause pain. Hidden pain in the hip is caused by more reasons, may also be related to hip arthritis, sacroiliitis, hip impingement and other diseases, if the symptoms continue to be unrelieved, it is recommended to consult a doctor in time, to clarify the cause of the disease, targeted treatment.