Get frequent headaches, sometimes constant for weeks. Had current headache month. Anxious. 22 yr old male very scared brain tumor. Ct year &1/2 ago was clear. Back of head, temples, gbm? What do I do

See neurologist. If the scan was negative the likelihood of a tumor is really decreased.Still need to rule out other problems that may cause persistent headaches so a neurology consult is the best route to go.
History and exam. Need to have a thorough history and exam. Just by thinking it might be a tumor must be stressing you out. Get to a dr. So you can hopefully get to the bottom of what is going on. Would consider getting more than one opinion. Could even possibly be a tmj/tmd issue.
Migrains, TMD. See your physician for a complete work up and examination. A common cause for frequent headaches is heavy contraction of the jaw muscles during sleep, known as bruxism. This is caused usually from an imbalance in the bite that manifests itself at night while asleep. As the teeth come together with only a few teeth touching, it triggers the jaw muscles to fire with tremendous pressure ; muscle pain.
?migraine. Your headaches most likely are of migraine causation, and extremely unlikely that you have any structural issue such as a brain tumor. You could possess sinus, dental, jaw, or neck issues, acting as a trigger. This needs a neurological evaluation, and treatments to break up the pattern, and would propose use of either preventative prescription meds or otc preps. Find headache specialist.
See neurologist. You need to get your headache under control and this needs a neurologist sometimes constant intake of nsaids , acetaminophen, or pain killers can cause rebound headaches which will only be relieved by gradual withdrawal of the medications. With a normal ct presumably after the headaches started, it is highly unlikely that brain tumor is your problem.