Lump behind right ear? Could this be dangerous?

Hi! Last week I noticed a lump behind my right ear. It's right behind my ear lobe, but on my neck (where the bone first starts) It's hard to touch but moveable. When being touched it hurts. I've been getting weird headaches on the right side of my head and getting dizzy. It's a bit bigger than a pea. I haven't been sick recently so I do not think that it's a lymph node. What could this be? Should I go to the doctor? I've talked to my mom and she said to see if it goes away but it's been almost two weeks and it hasn't gotten smaller, only a little bigger.

[emileegraceee]

Also I would like to add that I've noticed in a change in my appetite with this. I don't feel hungry as often, I also get nauseous. The headaches will spread across from the right side, then go down my neck, right to about the lump is.