Any good Afghani cross works well for managment of my back pain (Degeneritive Disc Disease & Sciatica), as well as severe insomnia.
At night, to help get through the night, and get a good deep sleep, I usually top my flower with a nice full melt hash.
At night, I have been having great success medicating with Afpak, a nice heavy hitting, 100% Indica cross. Very relaxing on both the body and mind.
For daytime use when my back is acting up, it's Afwreck. Still get that nice soothing body effect, but crossed with Trainwreck, the head stays clearer, although in a sorta cerebral kinda way
Another heavy hitter that I have had a great deal of success with, has been the Master P, found at So Cal Co-op. This is one very strong med, that is a wonder for aches and pains!
Good luck finding the strain that's just right for you!