Based on your answers, some of the most likely causes of your back pain include
disk disease
sciatica
muscle spasm or strain, or other minor injury.
More than one cause may present at the same time and other, rare causes, such as fracture, are also possible.
While over-the-counter pain medicines, a heating pad, and rest (balanced with activity) may be helpful, it is important that you see a physician to evaluate these symptoms.