I have had a bump on the right side of my neck for over a year now but it's gone down in size and doesn't hurt so I don't notice it much. But all of the sudden, yesterday, while on an airplane I noticed a new bump. It's on the back of my neck in the middle near the left side. It's about the size of a dime and doesn't move but it hurts when it's touched. What the heck is going on??