Sitting at the desk all day -> back pain -> excercises?

1st of all, exercise or not, you need to get up more frequently than you apparently are. The hours you do spend in the chair need to be spent posturally sound, which is very difficult to do as you forget to keep good posture as you engross in your work.

Exercises: (assuming no contraindications)
- lying prone, arms out, legs out - arc your chest and legs up twds the ceiling as if you're forming a shallow U. Do 20 reps.
- variation of this (more advanced) is to do same thing but w.alternating limbs, i.e. left arm, right leg and vice versa
- on hands and knees (quadriped position), head neutral lookin down, extend arm and contralateral leg (i.e. opposites again - left arm, right leg)
- prone position - on toes and elbows, hands together (or not if you prefer), hold your body level as if a bridge (what this is called). Hold 10 secs, working up to 60 over time as you progress in ability.

Start w.this stuff. Give it an earnest effort and some time for training benefit. It's no panacea but will help.

 

Missionary position. Not you. Her.

 

I follow the Athlete's Performance & Core Performance exercise models: http://www.coreperformance.com/

Here's the foundation book: http://www.amazon.com/Core-Performance-Revolutionary-Workout-Transform/dp/1594861684/ref=sr_1_1?ie=UTF8&s=books&qid=1247797962&sr=8-1

The other inescapable fact is that in addition to core strength, the most important factor in back heath is aerobic fitness. Perfusion to the tissues of the back is poor, so the delivery of oxygen and other nutrients requires good aerobic health.

It is neither simple nor easy I'm afraid.

 

Another good and simple excercise is to sit straight, suck your stomach in and hold it (the amount of time is up to you). It's a good way to work the abdominals.

 

Aeron Chair

 

So, the definition of irony......

About two years ago, my wife suggests that I buy a better chair for my home office to help my back. I order an Herman Miller Aeron chair and have it delivered to my daytime office. UPS truck arrives and we load the large and heavy box into my SUV. Once home, I ponder waiting for my wife to help move the box into the house, but my testosterone assisted brain decides that I can do it myself. The resulting re-injury to my lower back from leaning backward while carrying the large box slowed me down for at least 10 weeks. Stupid, stupid, stupid.......

 

Good book:
8 Steps to a Pain-Free Back by Esther Gokhale