Sometimes your anxiety will "make up" or "focus" on symptoms to distract you from other things. I went from no headaches ever to chronic headaches for a month straight or so after I started having problems with cervical dysplasia. It's funny - rather than focus on the actual health problem that I have, I worry about these headaches and think maybe it's a brain tumor. Rather than worry about my actual money/financial problems, I get myself worked up over random heart palpitations.
I guess my point is we HA people are really, REALLY good at focusing on either the wrong thing, or things that aren't really there. Work with a professional about your anxiety...try and focus on if you have real life (and when I say real life I don't mean things you've been Googling and are convinced you have!) issues or problems your mind might be putting on the back burner to focus on "other" symptoms.
With all that said: I had a brain tumor scare when my chronic headaches/pain/etc stuff came about. The general consensus as I understand it is MOST people with brain tumors do not only have headaches. I'm sure you read articles where it was "missed," but the majority of people who have brain tumors present with symptoms other than headaches...seizures. Changes in mental status. Loss of consciousness. Our brains are highly sensitive organs...if there's something growing in there that shouldn't be you would know about it. I had a friend who was diagnosed with a benign tumor when we were younger, she had it removed just fine...but it wasn't just headaches. It was headaches + debilitating nausea + vomiting + vertigo on a regular, daily basis...not just "headaches and random aches and pains." And regardless, she had it removed almost a decade ago with no problems...you'd never know it now to see her.
"ranging from aches and pains, muscle twitches, tingling everywhere, strange adrenaline surges, sleep jerks, loud gurgling stomach, eye pain etc." <---- I get all of these on a regular basis when my anxiety is acting up. Hell, I get some of these on a regular basis even when my anxiety is low. I get adrenaline jolts really, really bad when my anxiety is bad. I know what you're describing...that moment when you're about to fall asleep and for some reason you get a jolt of adrenaline and you sit up straight in bed as though something is about to kill you...yeah. I have gone 24+ hours without sleep because of those things at the worst. The problem is it's a cycle...the more you have them, the more you are afraid to have them, so you get revved up, and the more likely you are to have them again trying to sleep.
My mom gets them too. She's been getting adrenaline jolts off and on for about 30 years. They suck, but they don't mean you have a brain tumor.