I wanted to update everyone that is having this issue.
I believe my issue was an allergic reaction.
I am a runner; and I have quite a few allergies, and as the doctor put it, I develop my allergies--if I use a particular product or eat a certain food for a period of time, my body develops an antibody to get or keep that food or product out or off of my body.
My allergic reactions are usually: Breakouts on my face, itchy skin, and eyes and a runny nose.
I was noticing little pimple like bumps on my hairline and scalp for the last couple of weeks (before the lump on the right, back side of my head became painful) and I was having increased headaches.
I thought about anything new I had used for hair product lately, and I narrowed it down to either the Nexxan hairspray or Frizz ease mousse that I had been using.
Even though I wash my hair everyday, I believe that the product built up on my scalp, and after work I put my running clothes on and hit the trails just made the product easier to soak into my scalp.
What I did:
I used baking soda and mixed it with a little shampoo for the next few days while I washed my hair (a hairdresser gave me the tip a long time ago on how to get product build up out of your hair and to brighten your color, if you're a blonde) I stayed away from all product. and in 2 1/2 to 3 days my head / scalp ache was gone, no more little bumps on my scalp either.
I am staying away from all Mousse products, and if I really need to style my hair I will use a tiny bit of hairspray.and wash my hair with baking soda weekly, or bi-weekly.
I hope this may help someone else.