Pain killers and tens machine are the way for me too.
I get spasms in lower back right side, tens snaps the muscles out of the spasm, eventually, for me. But expect some seriously painful twinges that subside with time to a constant dull ache. So don't carry anything,ESP not valuable (or heavy obviosly) for a while after.
Gp ime is a complete waist of time when it comes to structural stuff, and physio or Chyro are usually too booked unto be a first response.
By the time an appointment is sorted recovery is under way. But there will be something pressing on a nerve somewhere so go see em.

In my case any form of treatment is hopeless until the muscles can be made to relax, which takes time for you to trust it not go go terWANG again. Rest, painkillers and tens, make an appointment asap for a couple of days time to get it manipulated when the pain is bearable....ime anyway.
Best of luck.