What is the best treatment for chronic neck pain & associated occipital headaches?

Several: Treatment for neck pain/occipital headaches may include: physical therapy, massage, accupuncture, trigger point injections, chiropractic and occipital nerve blocks. You may want to start with the least invasive treatments first.

OMM: What you are describing sounds like a cervicogenic headache. These often respond very well to osteopathic manipulation from the hands of a skilled physician. I would suggest seeking out a local do who uses omm to treat headaches and neck pain and see what they can do for you.