What i use for my boyfriends worst back pain is a homemade massage lotion its very potent. You can just mix the oils in some 90%+ rubbing alcohol.
You will need:
Tea tree oil
3 parts rubbing alcohol 2 parts pepperment 2 parts tea tree and 1 part lavender. Mix well and apply to affected area.
Just a heads up it will tingle. Helps with mucle cramps as well.
Also tea tree oil is poisonous if ingested take caution.