This is a great question.
I actually have two toothbrushes.
I have a colgate medium firmness which I use when I am not getting much pain in my arms and neck.
However, because I have a bad neck now and having surgery soon, I am using a Braun Electric Toothbrush with a rotating head. It is great for people who have this kind of problem with their necks. I would recommend it very highly if you have problems with your neck. It makes a big difference, Pamm x