What Causes Sharp Pulsating Pain In Head?

I have had a dulll headache mainly on the right side of my head more in the back with a pulsating pain through out the day but not constant, I've been getting occasional 2-3 times a day sharp pains through out the entire head and yesterday evening I noticed that I have a lump/bulge just under my hair line at the top of where my temple ends that developed with in hours, I have some sensitivity to light and I have no isea what this bulge could be but last night when I lied down I would get little pains from it