I'm sorry to hear you have pain in your back! I'd like to recommended two topical's that could work for you.
Aunt Zelda's // Cocount topical http://azcannaoil.com
Sweet Releaf // https://getsweetreleaf.com
Depending on where you are located you should be able to get these delivered to your home.
Hope you find some relief soon! Best,
Crystal Garden makes a massage oil that is 141mg THC and 50mg CBD. It works for me on shoulder tear and sciatica pain.