Is heat or ice better for low back pain? especially if there is a lumbar disk herniated? what are the symptoms of having a lumbar disk herniated?

Both : Both can help but it may differ from pt to pt sometimes it helps to go back and forth between heat and cold / if you feel one is much more helpful for you then stick with that / use apiece of swim noodle behind the small of your back while sitting as a "lumbar roll" I have found this to help many people including me over the years hope you feel better.