I feel for you. Missing out on a PR stinks. Case closed. I hope you feel better. You never know. If you do race, be careful. If you are feeling good, then perhaps give it a shot.
With regard to stretching, it is a tough area to stretch. I never feel a true stretch in that area, at least not as I do with other parts of the body. Let us know how you do. Interestingly, I have a race on the 23rd, and I am trying to make the same decision. It is a struggle. My body has improved a lot, but I am not sure about doing a race. Also, I am not in PR shape...though I have some pretty decent fitness, all things considered.
All the best...