Unfortunately, I can't tell you much. From what you have described, your knot is most likely a benign tumour. I don't think your depression is because of it...I mean it is possible to be caused by you continuously worrying about it.

However, the pain and the headaches signal that your tumour must be taken seriously. So, please put aside your feeling "stupid" about going to the doctor because you have no reason to feel this way. Everyone needs a doctor now and then and the fact that you work in a hospital doesn't mean you don't have to. If you really can't get over this feeling of embarassment then go to some other hospital where no one knows you. Whatever your choice, please go see a doctor. As time passes by, chances are your condition will worsen. Don't risk your health and life because of a silly thing...It is not worth it.

Good luck!

did you ever find out what it was?