I am a physiotherapist who also practises Acupuncture.
Acupuncture treatment either follows the Traditional Chinese Medicine (TCM) model, or the Western Medical Acupuncture model.
TCM is based on energy flow around the body, and problems are related to energy being blocked or over-produced. It describes problems in terms of the 5 elements of nature, and needles are inserted to normalise energy flow and balance the elements.
In Western Medical Acupuncture, the same points are stimulated by needle, but problems are described in Medical terms, so muscle strain, arthritic joints, etc. The needles are used to stimulate endorphins (natural pain-killers), relax tender points in muscles, stimulate circulation near an injury, and reduce the pain felt from problem areas.
You may need to try both to see which works best for you.