I know what you're talking about. I used to get that pressure feeling all the time, and sometimes if I read too much/overstimulate my brain, it feels like my brain is "screaming" (the only way I know how to describe it), which I guess is similar to feeling like your head is going to explode.

I don't get headaches.. haven't had a headache since my initial concussion. I guess this is just my version of a headache. If i lay in the dark for a while with a cold towel on my head, it definitely relieves the feeling and makes my head feel better.