I'm 28 years old but why do i feel hot and sweat all the time?

Some possibilities: Hi. Are you feeling hot and sweaty without fevers? How long ago was your brain surgery? You need to make sure there's no infection, post-op or otherwise. Damage to parts of the brain could cause the hot and sweaty feeling. Your thyroid should be checked. Are you cycling normally? Monitor your temperature; if fever see your doc pronto. Good luck!