The arthritis in my neck, which has periods of painful inflamation, also affects my head and eye. My shoulder muscles also feel painful particularly the day after the episode. What will help?

To help control the inflammation in your neck I would suggest taking Stinging Nettle from Vogel on a regular basis. This will help reduce the overall level of inflammation in your body and make it a lot less susceptible to flare ups. If you still have some flare up they should be much easier to manage and you should only need to apply Absolüt Arnica Gel on your neck to control it.
I would suggest you also look at the diet.
Consider consulting an Osteopath or Physiotherapist to make sure the alignement in your neck is corrected and that you do not have any muscles that are trying to pull it back out of alignement.
For more information on arthritis follow this link