Strict form for Barbell rows is flat back and no half deadlift movement as you row. Some do it with a slightly more upright stance but most important is to keep your back in its starting position.

Good luck. I had back issues for so many years I couldn't ever visualise a time when I wouldn't. And here I am now. No back problems. Just take it slowly. It's frustrating but worth it in the long run. I genuinely don't believe you can work through these sorts of injuries!