Arthritis is notorious for causing joints to become stiff, achy, and painful. While it is most common in smaller joints like the hands and knees, it's important to remember that your spine is one long joint. For anyone who has been dealing with arthritis, it is possible that a new or growing back pain could be osteoarthritis, or arthritis of the spine. This usually causes stiffness that is worst on waking up in the morning and at the end of the day. It is most likely caused by fluid buildup in the back due to inactivity which results in swelling.
The pain and stiffness caused by osteoarthritis can be eased primarily with heat treatment, though cold should be applied instead if there is any active swelling. Heat will relax the muscles and tissues around the joints and allow you to return to more comfortable activities. While arthritis is a chronic condition, many have found that back braces with pockets for heat packs are a great way to deal with regular back pain caused by spinal arthritis.
With any luck, this article has helped you clarify the pain you've been experiencing and given you an idea of how to treat it. If you're still wrangling mystery back pain without swelling, an almost universally helpful approach is simply to take a hot bath or lay hot towels or water bottles across your back while lying on your stomach.