Anti depressants are common, for long term sufferers, been on them since 96.
There are a few reasons for this, 1 it will get you depressed being in constant pain, this will in turn cause your body to become stiff, a normal side effect, this will make your back worse, the 2nd reason is to counteract the 1st, the more relaxed your body is the better for your back.
I have 2 splits in my pelvis, 2 spinal compressions a fused vertabrae, and a split vertabrae which presses on my spinal chord, along with this I have 100% full time sacro illiac joint problems causing muscle spasm, which aggravates the back which causes more spasm etc, this is also helped by my left leg being 1" shorter than my right.
I take citalopram as a anti depressant/anti psychotic medication, my brain damage makes me hear voices telling me to kill people I don't like, amongst other things ha ha!!
I am on the arm patches, these are morphine patches, they make tramodol look like smarties in effectiveness.
I would second the advice above, make a fuss it's your pain, ask for a referral to the pain clinic at the hospital where you are, these pain specialist actually do know what they are doing pain wise, and worth their weight in gold.
I would also see a private physio, my NHS physio was useless but when I saw Marcus Webb from Hadley Wood Health Centre, it was like someone turned the pain off, for years, general arthritis, wear etc have now caught up so even worse than before hence the morphine patches.
In 45 years I've found the pain specialists the only ones to see re back pain if it doesn't heal after seeing GP, I'm off for my 6 monthly contrast dye scan in january for this very problem, just make a concerted effort to sort asap the longer it goes on the less chance of effective treatment.
My current wait is a ulnar nerve transposition, and knee ops as both knees having floating cartiledge that needs removing.
Hoping all the best for you, pain specialist would be my first demand from doc.
Have they done the rabbit/seagull and box test on you yet, or is the pain confined to just one place ?
tabetha