Nape lump

[saa0527]

Hi, I'm a young adult that's fairly overweight. Just the other day I felt a lump at the back of my neck, right side. It seemed small, pimple-size, and so I didn't worry about it. However, it's been a few days and it seems to have gotten bigger. It's under the skin, doesn't cause much pain (generally painless, but sometimes if you press on it, it aches. Other times it randomly aches on its own), doesn't move, and seems hard (though I wouldn't describe it as rock hard). Does anyone have any idea what it could be? Of course when I google, it scares the daylight out of me because it would result as a malignant tumor. I'm hoping this isn't the case.