Herniated discs can be more painful at night due to the lack of movement during sleep. When lying down, there is less movement in your body.  This lack of movement allows inflammation to build and increases pain.  Additionally, certain sleeping positions may further aggravate a herniated disc by putting additional strain on it. To reduce discomfort from a herniated disc at night, try changing your sleeping position or using pillows under your knees or between your knees while you sleep.