You back ache seems to be due to muscle spasm as well as decreased fap in between lumber vertebrae due to which nerve compression is there and pain radiates to leg.As the paun is not constant ,nerve copmression is mild and it can be cured with Ayurveda treatment.Taking pain killers can cause gastric ulcer and will damage your
liver.So my suggestion is you should start taking ayurvedic treatment,do consult me for this.