One thing that will help your back muscles is core strengthening - I know this because I suffered from back pain for years. There's a lot of ways to do it and you can find most of them by Googling. Here's what I use, as recommended by my massage therapist:

Do this every other day, maybe more if you feel you need it. It works especially well when your pain is the most severe. In all the exercises make sure you tuck your butt forward and make sure your spine is straight. Hold each position for 60 seconds (or work your way up until you can hold for 60 seconds) and take a two minute break in between. Make sure you do all four positions in one session - if you don't, you'll regret it later. Remember, know your physical limitations! There is a difference between healthy pain and damaging pain.

1) Lying on your back, lift your legs up so that they aren't touching the floor. You'll need to experiment a bit to find out how far you can extend them and still hold it for the 60 second period. If you want you can lift your head up as well - this will strengthen your neck muscles, but is not necessary.

2) Lie on your side and balance yourself on the sides of your feet (however is most comfortable for you) and your elbow. Your arm from the shoulder to the elbow should be perpendicular to the floor. This position can be tricky to balance in, and at first might be harder on your arms than your core! Don't worry, you'll get used to it. Do this on both your right and left sides.

3) Get on your front as though you are doing push-ups, but instead of supporting yourself on your hands, use your elbows, once again keeping your upper arm perpendicular to the floor. This will probably be the hardest position to maintain - shakes are normal for me.

4) After doing all this, take a minute to stretch your core and relax. You should feel heaps better!

I definitely recommend that anyone with back pain due to muscular problems should try this at least once and see if it helps.