In shopping for weed, check the THC content on the label. Any THC content less than 40% is useless for pain relief.
Most buds sold in the stores are quite weak, ranging around 20%.
The following tip on my preferred strain may be unhelpful to you, as I believe that the hundreds of growers tend to make up their own particular strain names. I buy a strain of bud called " Alien Rock Candy." It has 40.2 THC, and it works like magic on my pain. I even get a pleasant relaxing buzz from it. And, of course, my music becomes cosmic. Then I fall asleep after several hours!