I've had a hard lump on the back of my neck for about a year. it doesn't move, its not painful and its getting larger. most likely cancerous?

See below: You need to have this examined and removed. See a physician. Your question cannot be answered without examining this lump.

Get it checked: It is impossible to render an intelligent opinion without actually seeing the mass and feeling it. I suggest getting it checked out soonest. Is it cancerous? Could be, but I can think of half a dozen other things that it could be. Bottom line, get it checked soon.