If you search for 'referred pain', you'll see the areas where pain emanating from the organs of the body is expressed.
In the interests of eliminating all possible causes, just check the location of the regions where pain from the liver (mid back on the right hand side) and kidneys (lower back on the left hand side) don't tally with the areas you are suffering discomfort. I only mention this because back pain does have a number of causes, not just lifting boxes incorrectly!!
The other comment that made me wonder was your burning sensation, although inflammation will always cause that.
Whatever the cause, several months is clearly too long and suggests an injury or condition that is not resolving itself.
We might be able to partially eliminate liver or kidney involvement if you can say that richer foods do not trigger symptoms, you don't suffer greasy stools and you don't have any discomfort when peeing.
That leaves injury or overuse and neither are getting better.
Can you change your driving/desk position? I've had neck pain and have almost resolved it with a change in seated posture.
I used to have lower back pain but resolved that through sit-ups to balance out the 'pull' between my abdominal and back muscles. I must say, the sit-ups helped in no time at all.
Five months is long-term, so we are beyond the point where a remedy (or pain killer) is going to actually resolve the underlying cause, so please do use our Atrogel as it does work brilliantly but I would suggest a good magnesium supplement (not magnesium oxide or chloride) and some posture work as outlined above.