What Causes A Sensitive Spot On The Head?

I am a 24 year old female with an extremely sensitive soft spot on the top of my head. When pressure is applied my whole head feels numb and it actually feels better. It hurts or becomes sore when I am stressed or have migranes. I had a small concussion when I was 15 - in which everything turned out ok. I'm wondering what this is? cause? issue? anything I can do to make it feel better?