Yes, my back kills me all the time from sitting too much and I'm only 26!
Here is what I recommend:
*Do farmers carries at least once a week.
*do front squats to help with your posture, I recommend doing them after deadlifts for high reps. Youre back/core will fatigue before your legs, usually.
*move around on your lunch break. Go for a 30 minute walk, do some light lifting, something. "I have no time" is a bullshit excuse, make time - your health comes before your job.
*be more active in general. Don't be one of those lazy assholes who gets home from work and just sits in front of the TV. It tough to do when the weather sucks, but when it is nice go to a park, go to the beach, do something fun outside youll feel better and so will your back. Besides, life is too short to be spent rotting indoors.
*obviously see a doctor. An x-ray can determine if the spacing between your spine is normal. If it isn't then maybe youll need an MRI, but you should still see someone.
*You could also get a standing desk, but I have heard mixed reviews about them and I have not personally used them.