I have stress-related tension headaches frequently and have been experimenting with head stretches. Stretching my neck from pulling my head towards my chest helps sometimes. I close my eyes pull my head down to where my chin is on my chest and try to relax my muscles and meditate.

Here's a link to some stretches. There are also videos on youtube (search for tension headache stretches).

This past week, I started trying herbs and vitamins to help with stress. Since I just started, I am not sure if I see improvement in reducing headaches yet.