Have pain in my shoulder, when i press it radiates to my head. having dull headaches in back of head...brain tumor?

Unlikely: Pain produced by pushing on your shoulder that radiates to the head is unlikely to be caused by a brain tumor. Headaches, in general, are common and the vast majority are unrelated to a tumor.

Muscle aches&brainCA: Most individuals in your age group would most likely have knotted up shoulder and neck muscles which will radiate to your head and give you regular headaches. Brain cancer usually causes balance changes, am headaches, nausea, seizures, focal neurological changes. You really need to massage your neck and shoulders on a regular basis and try to relax with deep breathing.

Not a tumor: Your description brings up the possibility that your headache trigger is located in the brachial plexus, and most pts with thoracic outlet syndrome have either tension or migraine headaches. If things get worse when you elevate arm above head, this may be answer. Might want to get this assessed.