I know people do not like running to benzos and I am not saying they are the only way but one benzo is prescribed for back spasms and issue and helps with anxiety and that is Valium. Its an old school med and I do not know why it is used for back spasms over other benzos but it does work. And it doesnt have to be a high dose. I recently started valium for emergencies and I am only allowed to take 1/2 of a 5 mg tablet.