About two years ago, while I was putting it up, I noticed a lump on the back of my neck
. It is under my hair, almost at the hair line, on the left side of my neck
on what feels like the left muscle of the spine, at the base of the skull.
I hadn't thought of it in a while, but more recently I have been getting massive debilitating migraines. That's why I decided to ask a question here. It is about the size of a dime, maybe slightly smaller.