Has anybody woke up from sleeping only to have a arm numb for months?

Pinched radial nerve. Degenerative disc period bulging disc. Carpal tunnel bulge of the disc without myelopathy

I used to get numbness in the same two fingers. It’s usually from sleeping on your side. For me, a thicker and firmer pillow almost completely eliminated the numbness. You could try sleeping on your back, or try a new pillow.

Yes, definitely try changing to back sleeping.  You might even lose the pillow and just row up a towel under your neck for support.