Every time you have sex, you will have pain in the waist and legs, which may be caused by overwork, or it may be caused by lumbar disc herniation, lumbar spinal stenosis and other diseases. 1. overwork: such as sex too often, or itself has been overworked, coupled with sex, may make sex after the waist and leg pain, generally do not need to deal with, pay attention to rest. 2. Lumbar intervertebral disc herniation: it refers to the structural changes in various parts of the intervertebral disc due to trauma, degenerative diseases, and other reasons, and the nucleus pulposus comes out from the ruptured annulus fibrosus. The main manifestations are lumbar pain, radiating pain in the lower limbs, numbness in the lower limbs and other symptoms. It can also be manifested as pain in the lower back and legs after sex. 3. Lumbar spinal stenosis: it refers to a series of symptoms caused by various reasons of lumbar spinal stenosis, which compresses the spinal nerves traveling within it. Mainly manifested as intermittent claudication, lumbar and leg pain, lower extremity numbness or sensory loss, urinary and defecation abnormalities, sexual dysfunction and other symptoms. It can also be manifested as pain in the lower back and legs after sex. There are many other causes of pain in the lower back and legs after sex, which should be emphasized, timely consultation, identification of the cause of the disease, and follow the doctor’s instructions for further treatment or therapy.