Physical therapy is an effective treatment for acute lower back pain

Patients who received physical therapy within the first 30 days of experiencing acute lower back pain had a lower chance of needing further medical services (imaging, injections, surgery, and doctor visits) than those who received PT later. 

Referring patients suffering from low back pain to primary care: Impact on future health care costs and utilization

The total medical cost of patients who received early physical therapy for lower back pain (within 14 days of onset) was $2736.23 less than those who received delayed physical therapy (early PT $1810.67, later PT $3661.78).