My initial reaction would be whether this apathy and lack of motivation started since you were placed on the drugs Lexapro and Elavil?
What exactly was the nature of the surgery on the back?
Was is skeletal or muscular?
I fell down two flights of stairs (a concrete staircase too ! ) about 20 years ago and my back has never been the same since. My back can "lock" that is to say severe muscle spasms such that I can hardly move as the muscles lock up, If I sit or stand in one position too long it becomes extremely painful to move again.
I don't like pain killers but there are a couple which are muscle relaxants as well as painkillers:
The first is called Voltarol also known as Emugel.-Chemcial name:
Diclofenac.
The second is Ibuprofen (usually a tablet), but in a gel form which you rub in to muscles in the affected area, and allows you to move more as it works as a pain blocker/muscle relaxant.
Finally I would get to see a physiotheropist (not a Chiropracht) together with the original surgeon who operated on your back and given them a detailed outline of the problems that you have had.
There are too many doctors out there who will just reach for the prescription pad without doing a proper examination. I would ask that the do an examination includes a CT Scan, and X-Ray if it is the actualy bones in the skeleton which are causing the pain.
I am wary of chiropractics since I did use one for about six weeks when I first had the injury, and actually between the two of them I actually felt worse than I did before they started working on me.
I still have problems, but I only use medication when I have to, and since you have been subject to surgery recently, you should follow it up.
Best of luck, and can only sympathise with you since I have a rough idea what you are going through.