Some antidepressants have been successfully used for pain. Cymbalta is commonly prescribed for pain and Effexor has shown promise in studies for pain. Some of the older Tricyclic antidepressants like Imipramine have had good results on pain. I have never heard of Zoloft being used for pain however. I suppose it could possibly work by the way it increases synaptic levels of dopamine but Zoloft is only a weak dopamine re-uptake inhibitor. Diazepam, also known as Valium, has muscle relaxant properties and could be potentially useful for pain. I question the prescribing of Zoloft however. I would think you would be better off on Cymbalta or, if its too expensive, Effexor for pain. I'm not sure what country you live in though. It's possible Cymbalta and Effexor aren't available where you live.