Sciatic pain. The sciatic pain can be caused by spinal stenosis, ruptured disc, nerve impingement ... The treatment depends on the cause of the pain. It might include strengthening exercise, physical therapy, medication, interventional therapy ... You should seek help from a health care provider, you might benefit from a comprehensive evaluation.
Varies. Usually begin with progressive exercise regimen as tolerated with consideration of taking oral nonsteroidal anti inflammatory medication.
Core Exercises. Typically core strengthening exercises are the best to help relieve pressure and forces in the spine. I would try and google some or look them up on youtube to see descriptions. If you can do them yourself, wonderful otherwise ask your doctor to get a referral to a good physical therapist for further assistance.