i have chronic back spasms from a wrestling injury when i was a child, the old tricks work the best but you must do them regularly
ice 20 min heat 20 min repeat, do this every night. ib profen and naproxen can help but they are more for joints. muscle relaxers can help some but have never worked for me.
massage is very good for getting rid of spasms. and yes it is quite painful, but you really need to get in there deep and work out the lactic acid built up in the muscles.
if they persist, go to physical therapy and have ultrasound done(this is awesome, it dissolves spasms)
Do you use a vaporizor? after you vape the bud scoop it up and put it in gel tabs, this works great, as the canabinoids that help with pain are still in the bud but the thc is not- pain relief with no high.
the three top causes for back pain are bad posture, poor flexibility in the hamstrings and weak stomach muscles. work on this and the problem should subside.
no amount of pain medications will ever get rid of back pain, it will only destroy your liver. if you are serious about wanting to get rid of it you must make lifestyle changes i.e. get in shape, stretch, eat good, etc.