I've got an awful back from a summer job. It's been so bad that I had to go to a physical therapist and that still didn't really help. I've learned to live with the pain but I still have to work hard to keep the pain down.
Some workouts my physical therapist had me do:
1. Lay on a yoga ball and raise for example you left arm and right leg and vice versa. Be sure to suck in and push your abs into the yoga ball and try to rely mainly on them.
2. Start with your arms clasped, resting your forearms on a yoga ball in an upside down V. Then roll out over the ball till you're in the position pictured below. Then roll back to the starting position. This will work the core muscles that help to stabilize you.
3. Last good workout is to lay flat on your back with your legs on top of the yoga ball. Start with your calfs resting roughly on the center of the ball. Then lift your stomach and back up of the ground so your in a sort of upside down plank on the ball. Then roll the ball towards you using your legs till its just your heels on the ball then roll it back out away from you. This one will make your hamies absolutely burn. (also pictured below)
My favorite stretch of all time is this one: Lift on leg up an set it upright on the corner of a wall with the other leg stretched straight past the corner. Then with about 8 inches between your butt and the wall, put a slight bend in your knee and push your heel straight into the wall for ten seconds, this should tighten your hammies. After the 10 seconds straighten your leg and scooch in towards the wall a little and stretch it holding it for around 20 seconds. Do this 3 times for each leg. The 8 inches is just a rough estimate. I started around 12 inches from the wall. But just start at a comfortable spot so that as you scooch in the 3rd time you get a real good stretch without killing yourself.
Another one is the straight up Bend-Over (This is NS I need at least on sexual reference), with your legs together. I like to do 10 seconds down, stand straight up one leg over the other 15 seconds each then finish with a 20 second with no legs crossed. Be sure to stand straight up between each to give your back that slight recovery second and to realign the muscles before the next stretch.
I have a ton more stuff so if you need anything else just PM me and I'll be sure to help you out.