I have worked with three acupuncturists and I think they all would agree that acupuncture works better for some issues than for others. The guy I currently go to only deals with orthopedic patients/clients.
Obviously, if there is something structural wrong with your back, acupuncture is not going to have an effect. It may help the pain somewhat, but it probably will not heal something that requires surgery.
Also, acupuncture is not a fast-acting treatment. It usually takes a series of treatments and sometimes the healing is so slow that you're not really sure it is going on at all.
I don't know what you are specifically interesting in learning. I'm happy to answer any questions, if I can. Also, there are many older threaRAB talking about acupuncture.