Ah yes, Occipital Neuralgia, or O.N., I know all about that!
I have had the nerve blocks 3 times now, and they have worked well for me, and reduced the pain a lot.
I don't know much about MS, and the problems related to it, but I'm sure it wouldn't hurt to try the nerve block, to see if it will help with your headaches.
I don't think it's like a lumbar puncture (not that I've ever had one!), the needle used in a nerve block, is quite small, and not very painful at all. Well, it wasn't when my Neuro did it...and I hate needles too!

~Jaime~