Hello Mary,
If you are truly worried you could ask your Doctor to do an MRI looking for a tumor. However, that being said, one can develop a new headache from a variety of causes, including (rarely) brain cancer/tumor. You have recently had a CT of the brain and all is clear. Only on basis of your headaches one would look for other causes before suspecting brain cancer/tumor.
Is it theoretically possible that this may be brain cancer/tumor ? The answer is yes, it is theoretically possible. However, is it likely that you are dealing with brain cancer tumor? My answer would be no. I would seriously doubt it after a normal CT scan but please remember I am not a Doctor.
It does feel to me like your Health Anxiety has kicked in and having a brother who died of a brain tumor makes your mind more susceptable to worrying about a brain tumor. You have my sympathy at the death of your brother.
My sister died of Ovarian Cancer in 2009 and I had my Doctor run the CA-125 blood test just to reassure myself although I truly did not have symptoms but let my anxiety take over. Once I knew the test was normal I put the thought out of my mind. So big breath and know we are here and that we care. (((Hugs)))
Kindly,
Kitt