My personal feeling is that chiropractic is a bunch of B.S. When I was much younger and less of a confirmed skeptic, I saw chiropractors a few times on occasions when I had "tweaked" my back (by "tweaked", I mean that seemingly common event where your lower back bothers you, often out of nowhere, and it's really difficult to bend over or do just about any normal activity). And it seemed to help a little, and eventually I got better.
In later years I noticed that on those occasions when I would tweak my back and NOT get any treatment, it still got better in the same way as it did with chiropractic treatment, i.e. several days to a week or so later. It reminded me of the joke about Vitamin C (or Zinc or whatever) and having a cold; with massive doses, your cold will only last 5-7 days. Without taking anything, your cold will last about a week.
Some chiropractors are downright kooky, and think they can fix anything by cracking your back. Others, to be fair, can be somewhat helpful. I have a good friend who is a chiropractor and also a former competitive runner. He treats a lot of running injuries. Most of his treatments seem to involve ultrasound, massage, stretches, strengthening exercises, and so on. He seems to be fairly effective; or at least, his clients like him. I do sometimes wonder if he ever thinks, hmmm, maybe I could just do away with the spinal manipulation part altogether.