This is an enormous task as you have had a lot of injuries and surgeries that are interfering with how your nervous system can gather appropriate information from the area and allow you to get back to moving well. I would get on the site and start with the “I’m in pain” tab and get to work on anything it discusses for the lower back, particularly with breathing tied in. Getting into the Art of Breath course by Brian McKenzie can also be very helpful as it can help you shift the state of your body through tapping into your physiology through focused breathing work. With so much trauma to the area, the road back is long and it is multifaceted. You have to look at sleep, hydration, lifestyle factors and environmental load that could be causing compounding issues. Look at training and any way you can start to add load to the area. I like to have people with severe back trauma and multiple surgeries do sled work, pushing and pulling and so on. You can typically start loading the system without a lot of negative consequences.