Good Morning Flexibility

I’m recovering pretty well from a back injury from last Christmas and just starting the good morning movement with no weight whatsoever.

I find that I cant go much more than perhaps 45 degrees past vertical while keeping the lower back arched. Am I doing something wrong or is that entirely reasonable considering differences in flexibility from person to person and my injury? I do feel it in the hamstring and glutes even at the limited range of motion.

Doesn’t really seem like a problem.
If you keeping your lower back arched you won’t be able to go down as far. However, if you can only go to 45 degrees in this manner, you should work on your hamstring flexibility.