Unexplained swelling in head...scared.

At first my head hurt terribly bad. Now I have a big knot in the back of the right side of my head. My right side of my face feels a bit swollen too! My neck and shoulder hurt so bad that I cannot turn my neck or lift my right arm. This all happened within a 48 hour period with no cause that I can think of. I am only 23 years old, and this is scaring me. I have no medical insurance right now, so I need your advice. I could always go to county, but if you all think it is something minor I would rather not be out the money. I do not have $ to spare! Please, does anyone know what thios could be from?