if you have sciatica pain, it is likely some disc bulging into the nerves of your spine.  this fires up the muscles – depending on which disc it is, it can be only in your back or go all the way down the back of your leg to your knee.

i would find a good PT to help you deal with the spine issue.  along the way you can use some gentle MWOD mobs to relieve muscle tension, which should help with pain.  this would be mobs on the QL, erectors, all around the glutes, hamstrings.  i would recommend starting with softer tools like the alpha ball until your condition has improved enough to deal with harder tools like the supernova.

posture work will be important also.  likely that is what caused the problem is improper posture and bracing during lifts, or exceeding your body’s capacity to brace during a particular lift.