Not necessarily. It is an option.
It is a good one. I guess that depends on who is answering this question but it is an appropriate choice & a good one, it is not the best as there are other options including, rest, activity modification, medication, massage, heat and/or ice applications, a simple back support or chiropractic as well as even acupuncture. It is a good way to learn back exercises & correct biomechanics to avoid a recurrence.
Does a lumbar strain ever go away? I've had pain meds. Inflammation meds. Physical therapy. Its been a year and a half since my incident
Find pain generator. Strain is a nonspecific descriptor of symptoms, and does not explain causation, or actual source of problems. Consider sacro-iliac dysfnctn, hip problems, pyriformis syndrome, postural and reconditioning issues. Perhaps visit a nearby osteopathic physician and investigate some of these issues, as much if not all can be reversed once diagnosis is reached.