A lie down back pain can be caused by the following causes: 1, lumbar spine tumor, when the lumbar vertebrae and accessories have tumor or metastases, can have lie down back pain, especially at night when sleeping pain is very obvious, this is a tumor resting pain, this time to early physical examination, check the lumbar spine MRI, CT to early diagnosis and treatment; 2, lumbar back myofasciitis and lumbar muscle strain, this disease When these two diseases are serious, there can be lumbar pain when lying down, and there can be heavy lumbar pain when waking up in the morning, which can be improved after a while of activity. This can involve the entire spine, so blood tests and x-rays of the sacroiliac joints and lumbar spine are needed for diagnosis and treatment.