When I went to bed at three AM last night, my neck was completely fine. But when I woke up at nine AM, I felt the side of my neck (towards the back, behind my ear, but in the very middle of the side of my neck) and found a huge, painful lump the size of a small shooter marble.I know it can t be cancer, because cancer doesn t show up in the middle of the night like this, and I was playing with my hair last night before I went to bed, so I know it was most definitely not there when I went to bed.It s quite painful. It feels like a huge muscle strain, honestly. Sort of like I overworked my neck in the gym (which didn t happen, as I worked the late shift at work last night) and it s just sore from the workout.