I have found a knot about mid ways up the left side of my neck. It is about the size on a dime. Not sure what it is
Its just muscle tnsion you can fix it yourself by using your plam and aplying light pressure at first in a downward motion or you can just go get your whole neck worked on at a massage parlor or something of that sort.
Knots can be worked out and are muscle problems, but if it is still there and you are worried that it may be a tumor, have it looked at right away! They can do an ultrasound to see what the lump/knot is and if they think it's suspicious, they'll do a biopsy. Lymphoma and thyroid cancer are two cancers I know of that can present themselves through a lump on the neck. I recently had a lump on my neck which was a nodule and was thyroid cancer, so maybe I'm a little over cautious in suggesting these things based on what you said, but it's been two weeks so if you're still worried and it doesn't seem to be a muscle problem, I'd get it looked at.
This could be a problem with the lymph nodes you should get it checked out if it doesn't go away after you've tried the suggestions above