Well that depends on if it works or not, doesn't it?
If it works for you, it'll be $4k very well spent. Otherwise, it'll be a waste.
See if you can find a good one. Like many others note, they sometimes don't get much schooling. However, many states, like my own (Georgia), screw them over as far as what counts towards getting a degree, so they often have to go and do their learning in other states and such, with nothing on paper to show for it.
However, even if you find a good one, look into other options, like physical therapy, yoga, etc., as it is very possible for many times of treatments to not 'stick'. This is a common case with back and neck pain. Very often other problems will get to fixing themselves, but between you going and getting fixed, then going back to doing whatever caused it to go out of whack again, your body gets used to the pattern. Best is to get treatments and include some kind of workout or something that could help the muscles and such in your back keep in shape, and help your body cope better with temporarily over-working it.