6 years ago in 2007, I was working in a food place at my job and dropped a heavy box on top of my head in the freezer. About a month afterwards, I was having tingly sensations from the back of my head that traveled to the top around my sinuses, or would travel all over my head. Sometimes it can cause a dull, throbbing pain on the top of my head or at the source of the tingling as well...it varies. I have seen 3 doctors, only one was able to tell me that it was a massive concussion and that that's what had caused this. I've noticed some changes in my cognitive abilities and my equillibrium and my balance are off as well. It's been 6 years, and now while it doesn't happen as often, it does still happen, but with more of the pain along with the tingling sensation. I'm wondering if something else could be wrong as well and what I could do for treatment? And do symptoms like these usually happen for more than a year?