Based on your answers, some of the most likely causes of your back pain include
fibromyalgia
ankylosing spondylitis (or related conditions, called spondyloarthropathies)
muscle spasm or strain.
Other, rarer, causes 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.