I have an eternal nagging injury in the same area from a car accident.
At least once every 3-4 months it acts up and debilitates me for a couple of days.
Stretch the lower back helps a lot. Lay on your back and elevate your feet. I use a Swedish Exercise ball so I can roll it around with my legs to force my lower back muscles to stretch and loosen as well as to re-situate the discs that have jostled out of place.
Also, Cold compress for the first 24hrs and then hot after wards will help take down some of the pressure that is being exerted on the nerves.
And I always take a couple of Motrin 4 throughout the day of the injury.
Another thing ,is to sit in a hot tub. I have done it a few times and it really did help.
Feel better!
VR