I forgot to add that since you have a history of TBI, there are so many symptomatic problems that can come from such a thing, that you should be under fairly constant care of a neurologist, perhaps a second one in your case if you're not satisfied that everything has returned to normal.
The cranial bones are nearly completely fused at age eight, but it takes to the age of 25 for them to become solid bone. You can google "age skull sutures fuse," sorry I didn't copy the links I found on it, there were a lot of articles I read to settle on the right age. As for my general knowledge, the brain still develops on up into the early 20s, which is how come teens, for example, can't "see around corners," as Dr. Phil would say.
I don't want to put words in your mouth or assume anything about you, but if you have been talking to a neurologist and are curious about this, because perhaps you are experiencing a sensation out of the ordinary in your head, a neuro can order a CAT scan to see if it's neurological, or you can visit a psychiatrist to find out if it's a mental disorder that can be treated to make it go away, or you can have your physician keep an eye on how your heart is doing because a problem with the circulation system can cause your head to feel strange.