Guess who's back back again BACK ARM PAIN //

Wow! Shockingly haven't posted on here for a while!
So you all know me as the 17 year old girl who is absolutely convinced she has heart problems! Soo okay, I still have the anxiety over heart problems but I'm not getting the chest pain anymore.

So I got a massage yesterday and omg I felt cured for the entire day! I hardly felt anxious and barely had any symptoms..it was amazing. I knew it was too good to be true tho. The man who gave me a massage said my neck felt really swollen (idk if that was the word I can't remember) but he was massaging my neck) And he said he felt a few knots in my back...so I was researching and now I'm convinced I have a tumour in my back or something.

My back only hurts when I'm lying down. When I'm up and about it's fine even doing exercise it's fine but when I'm lying down nope and I read that can be like a sign of a tumour in the back.

I have a few questions ;

-Could I simply have tension in my neck thats causing back and arm pain?

-My back pain started when I went to A&E..as did my arm pain. Isn't it a bit funny how they started when I was at my worst? Like could they genuinely be nothing?

Ugh I'm going out my mind AGAIN.

Put in bold the important things in this as I tend to ramble on.

Also need info on fibromaylgia (idk how to spell it? probably dont have it either just deciding to diagnose myself with something else