hazel,I am so sorry to read your pet had to be put to sleep. With all the stress in your life it would not be unusual to have headaches and tension in your neck and shoulders.
I have a lot of tension in my neck which is really irritating. When I realize I am sitting with my shoulders hunched up to my ears I practice some of the breathing exercises from our resources as well as stretching exercises.
Putting something warm on your neck also helps reduce the anxiety that you are holding in.
Take care,
Kitt