Based on your answers, some of the most likely causes of your back pain include
muscle strain or spasm.
degenerative joint disease (or osteoarthritis)
ankylosing spondylitis (or related conditions).
To decrease pain, rest the back and avoid overuse. Over-the-counter pain medications, a heating pad, and topical treatments (such as Icy Hot, Ben Gay or ice) may help.
While these measures may help, it is important that you see a physician if symptoms are getting worse or not improving over time.