Hi there and welcome to HCM ,
First of all I'd like to appreciate your patience for bearing so much pain for so long which is really hard.
Secondly, I think You've underwent decompression surgery in 2009 most probably due to some traumatic
brain injury causing blood clot in side.
Its really unfortunate that you got hit not even after 3 months after surgery
well u didn't mention when did u fall and how and fall from where??
Was it immediately after you got hit or later on , it'll be great if you can throw some light on regarding this..
Are you also experiencing any weakness particularly in any part of your body(perhaps during walking??)
Are you under follow-up of your neurosurgeon?? Did you miss any follow-up ??
what all symptoms are experiencing along with headache??
Either way the answer is very simple-- Don't waste any more time and please visit your Neurosurgeon at the earliest(if unavailable then just rush to your nearest ER) and also get a Repeat CT-Scan head done to see how the things are really and get back to me whenever possible
Thanks again for contacting HCM, Happy to help