Pain and stress near where the tendons attach to bone is a warning sign, perhaps of over extending or over exerting the muscle. Tendons take an awful long time to heal.

It's not that rare among us older folks.

I recently fitted a Brooks Swallow to one of my bikes, and it hurt on my left sitbone due to the new hard leather. I could also be sitting on the cantle plate, I'll have to check that. Rather than just HTFU, I rotated the saddle a little bit at a time, moving the nose toward the side that hurt. That equalized the pressure on the two sitbone contact points.