Here in Canada we have GP's, too.
Regarding this being all in our heads...I have so many symptoms, my brain can't keep track of them...so I don't think I'd be able to make them all up...way too many. I can't even remember them when I have to tell someone what they are.
I'd rather have Lyme than Fibro, too. I do not want a diagnosis of something that they just treat the symptoms for...I don't want a life of pain killers. Even if the Lyme is difficult to treat, at least there is hope to irradicate it...or send it into remission.
But regarding pain - my pain is pretty bad...it flares most afternoons, evenings to a pretty high level. I'll plug my ears if you try to tell me I have Fibro.