Joint pain pain and back pain are not two foreign areas of study. By definition a joint is "the point of contact between elements of an animal skeleton with the parts that surround and support" (Merriam Webster). In fact, the spine itself is made up of several joints.
The old story of grandpa complaining about his joints or someone saying, “It’s going to snow. I feel my knees.” Has some truth to it. But before we explain the reasoning why the pain comes on we should probably explain what is inside the joint that causes pain.