I'm generally inflexible but my shoulders and back are by far the worst problematic.
I want to be able to keep my hands straight above my head, but in general i am working towards doing (a) muscle-up(s).
Nothing is really stopping me. I have my fysio exercises that start to slowly improve things. I mostly have to just stick to them and do them at least every other day (most of the time i exercise different muscle groups every day).