Physiotherapist Richard Watterson replies: Firstly, sitting for long periods of time on a regular basis can give you chronic lower back pain. The main causing factors being poor sitting posture and incorrect seating. I would advise that you take regular breaks to stand, stretch and walk around. I appreciate that while at work it's not easy to take a break, but this will help your back by varying the load placed on it. You should rearrange your chair, desk, PC, telephone, etc to allow you to adopt a better sitting posture. For further details www.backpain.org offers lots of useful advice.
Secondly, a massage is usually relaxing and beneficial to a tired, aching back. But if it is too deep you run the risk of putting pressure on areas of the spine that can't tolerate it. Someone who is skilled at massage can apply deeper pressure as they know what they are dealing with.
I suggest you improve your ergonomic set-up at work, take regular breaks and reduce the intensity of the massage or see a professional masseuse.