Pinched nerve in lower back

[Hipster]

Hi, I’m new and have always had extremely tight hips. I did the first half of master the pancake the other day, and a couple of days later got a terrible pinched nerve in my lower back. My guess is that the tight muscles etc around my hips were actually helping hold up my spine, and when they relaxed a bit the spine compressed with nothing to hold it up. My core is very weak and I am long waisted. Does this make Sense? If there is some truth in my guess, after this pain heals, should I work on my core before doing more stretches? I also was really pushing the stretches. I hadn’t exercised in a couple of months before this. Any insight would be very appreciated. This back pain has been terrible, and I really want to age in a strong, flexible fit way. Other info that might help: I am 48 yr old female. Thanks! Cary