HI Heather

Welcome to neurotalk. Try not to freak out. Fear makes things worse than they are sometimes so don't let the fear get the best of you. And don't assume all the symptoms are connected.

You have found a good place with lots of people who are smart and listen.

I have a couple of thoughts for you. First if you are changing positions and it goes away it sounds like a nerve compression issue. The sensation down your spine sounds like a l'hermitte's sign. I get that too. My injury is in my neck but the effect can be in my legs too.

Lets see what the MRI says. That backpack could have put some pressure on your cervical and thoracic spine. Also be sure to ask the doc to do x-rays to accompany the mri because sometimes when you are laying down the mri does not catch your spine in motion. If he does agree to the x-rays ask him to do flexion x-rays back and forward to see your c-spine in motion.

Thyroid can also cause fatigue and pins and needles. Ask your doc to check you for that too.

So try not to jump the gun. , we are here for ya!