Based on your answers, some of the most likely causes of your back pain include muscle spasm or strain, or degenerative joint disease (osteoarthritis). Less likely is a fracture, from trauma or osteoporosis; other causes are also possible.
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 brace, rest and ice may be helpful, it is important that you see your doctor to evaluate these symptoms.