I also suffer from trigger points and horrible tension headaches, with some dizziness. Go to the headache board at health boards and look for the post called Chronic Tension Headaches by boxerlover. There is a bunch of information on this post about this very subject. Mine are also felt between my shoulder blades as well as neck area. I have found using a tennis ball against a hard surface, meaning the floor or a wall, back of a chair really helps break the knots up!
The post I told you about I think you will find very helpful. You may need to search through it, there are 100 and something responses!!!
Good Luck I hope this helps.