What Causes Headache While Having Lump On The Back Of Head?

I have a question about a lump on the back of my head...it appeared three weeks ago and it hurts when I put pressure on it. I also get a throbbing pain from it and wake up with headaches. I went to my nurse at my college and they thought maybe it was a cyst and put me on antibiotics but it's been over a week and nothing is working