I Have Noticed In The Last Month That I Have

I have noticed in the last month that I have this pretty good size lump on the back of my neck and its on the spine part near the top just below my skull slightly. It doesn't hurt but its concerning as I have never felt this before. I have also had some pain in the back part of my shoulder as well. I am not sure if this lump I had found has something to do with the pain I am feeling or if the pain is do to a way I am sitting at work.