It's Not A Tumor!

A few years ago, during my Senior year of college, I found a lump on the back of my head, in this general area:
It didn't hurt at all, and was sort of squishy and a little mobile. A little while after I first noticed it, I went to the eye doctor to have a eye exam done. I have terrible vision, so I get an eye exam about once a year to make sure that my prescription is accurate. I mentioned the lump for some reason of other to the eye doctor, who promptly told me that there was a good chance that it was a tumor and set me up on a series of tests to determine if the tumor was affecting my optic nerve. The most disturbing part of the whole thing was that she basically talked about the possibility that I had a brain tumor in the same manner that another person would discuss the weather.
Most of the tests that I had done that day were inconclusive, so I went to Student Health to talk to an actual doctor. I explained to her how long the lump had been there and the eye doctor's concern that it was a tumor. The doctor proceeded to feel my lump and "hmm" to herself. After a few minutes of this, she told me that she wanted another doctor to consult with her about it. She brought in another doctor, and the two of them stood over me, prodding the lump on the back of my head and saying, "I don't know, what do you think it is?" I was not amused.
The first doctor set up an appointment for an MRI for me, which I was not too excited about, since being in enclosed places freaks me right the hell out. As my friends know, I am uncomfortable if I can't see the door. Pamala always let's me choose where I want to sit at restaurants, one of the many reasons why I love her. But I digress. So, I went and submitted myself to an MRI of my head, which was one of the least fun things I have ever done. For those of you who have never had an MRI, it is loud, which is enough to freak you out even if you don't care about a giant machine suspended a mere inch above your nose.
The results of my MRI? Inconclusive. But they were able to rule out it being a tumor, so that was an improvement. But I still had a mystery lump on my head. The next candidate for what it could be was a blocked blood vessel, so I was set up for an ultrasound on my lump.
By this time my wonderful roommates were doing all they could to make the situation funny. There were jokes about my brain trying to escape, alien pods, and super powers. They even named my lump Noam. I was taking a linguistics class at that time. I'm sure that about two people who read this will get that joke.
So I went to have my ultrasound, which involved a bunch of very cold goo in my hair and the technician going, "Hhmmmm...I don't seem to be seeing anything here..." for about half an hour. They were able to determine that I did not have a blocked blood vessel. However, no one was ever able to figure out what it actually was. It magically disappeared a few weeks later.

Now it's back. It seems to be different this time. For one thing, it is painful, even when I am not poking at it. It also seems to be two small lumps that are very close together. At least, it hurts in two distinct places on the lump. One part on the bottom, and another part on the top left. The bottom is much more painful than the top.
All I have to say about this is what the fuck!