I was told by one therapist that headaches early in the morning, or that are worse in the morning can often be from neck issues not always but, bad posture, whiplash, etc, at first I didnt believe that however after months of having my neck worked on it has reduced morning headaches, unless I do something dumb or sleep funny, or there is just the odd weird one. Not saying that is the cause but worth looking into.. I now usually start the day without one, just takes a bit for it to come on, over stim etc... also mood, anxiety, depression all stuff that can stem from concussion and life circumstances can present as headaches

Hope it gets better, its daunting when you wake up with one!