These headaches

I for some strange reason am having these really bad headaches lately. It seems that they are in the back of my head where my neck connects to my head. they are sometimes so bad I don't think that they are ever going to go away. I am trying to figure out if they are caused from my computer or something else. Tylenol does not seem to be helping, but I don't want to take it to often since I am sure it is not good for you. I might have to get some other medicine tonight.