I had SJD with DS2 as a result of muscle separation from DS1. Not sure if this is what you have. It was incredibly painful. I had a belt and tubigrip.
Physio was great for SJD. Taught me exercises. Also showed me what to do and what not to do to help. Like the best way to get in and out of the car etc.
If you have SJD then physio is brilliant IMO.