Take care 🙋🏻♀️🙋🏻♀️
Best route may be dynamic stretching (not static) but hold off on actual exercises until you have good, free, full range of motion. Don't overdo it: as they say in Vietnam, "slowly, slowly catches the monkey".
Here is a guide to safe stretching, but do not push if you cannot do perfect form on Day 1:
Also, walk at least 10 minutes twice a day, even if painful at first.
Best wishes – over time you will build a strong & less painful back.
Unfortunately the kind of injury could cause very specific individual needs . and it should be addressed with utmost attention to your specific problems and the way your body reacts to certain stimuli.