You ask a very good question, however, it has no easy answer. There is no one specific person who is best equipped to treat back pain. While the back pain may seem common from person to person, the different causes of pain and the individual patient circumstances can change who would be the best treating professional.
Some people feel best by going to what is called allied professional, such as chiropractors. Others would prefer to only see a doctor – but it could be one of many different specialties. A family physician with experience treating back pain may be the logical choice for some people, but not others.
The problem with treating back pain is that there are so many options that you could have five people with very similar back pain all being treated differently.