In most cases we cannot pinpoint the exact cause of the problem. X-rays usually don't help and expose the body to radiation. Most back pain comes from the muscles, ligaments and joints. Gentle exercise will return them to normal condition. Stress increases the amount of pain you feel.
Tension causes muscle spasm and pain.
Back pain often comes in spasms. It gets better over a few days then recurs, gradually returning to normal usually within 4 weeks. Pain travelling down one leg worse than the back pain, is usually nerve root pain or sciatica. It can reach the foot and be associated with numbness and tingling. The treatment is the same provided the pain is resolving within 4 weeks.