Hello Pete,
Welcome to the community.
It would be more helpful (for me) to know more about your practice. It would be like you asking me “what’s wrong with my blocking” without telling me anything at all about the blocking in question.
First and foremost, Yoga is not asana (poses) but asana is contained within Yoga, much the same way hitting and blocking are not martial arts but they are contained in martial arts.
Second, the practice of asana is not a stretching practice though it too has stretching in it. It is a practice of self-discovery which physically involves stabilizing some things and mobilizing others.
These things aside, stretching is generally effective when it is slightly uncomfortable but before it is aggressive, violent or injury-inducing, harmful, or “pain”.
Soreness in muscles that are either overworked or worked after dormancy can last for several days, depending on your self-care. Any muscle soreness lasting more than three days is cause for a deeper look. Further, the muscles will become accustomed to the work (assuming it’s replicated over time) but there is no fixed time for this and it is helpful to allow said muscles to recover as that is “repair”.
Is this information helpful and does it answer your questions?
warmly,
gordon