I broke mine twice, not sure which number, but up high between the shoulder blades.
Both times I fell in soft sand landing on my head and shoulder.
For me, it does not seem to get better, but I seem to have more lower back problems/pain.
The problems with the upper back bother me when I do some things that make me stand and work slightly bending over, like say washing dishes over a sink that is a bit too far away.
The lower back and some other bones broken in the past bother me way more then the upper spine thing, but all together, its getting hard to ride (or drive) for long.