Close to 25 years of acute lower back dramas
Mine is facet joints due to my discs losing height
Basically my back has had a hard life
You really have to learn to listen and learn how to manage your back, when sore ice is better than heat, when feeling sore keep moving but take it easy, as it can be arthritically induced
Stretching especially hamstrings can be very beneficial, a strong core imho is paramount
You don't need balistic regimes like heavy weight squats etc, a set of power bands are great, especially on one leg as your using your core to balance , stand up paddle will see great results, cycling especially uphill out of the saddle, losing weight, eating healthy, cutting back on the grog ( alcohol causes inflammation)

, I spend close to 20 mins per day hanging off a beam in a relaxed state to open my vertebrae really helps me, seat harness can cause compression and stop your core working compared to a waist harness,
There's nothing worse than back issues imho it's the most debilitating injury , I'm always looking at different exercises for my core,
Get pearced ( kite world )by Matt Pearce has some great core focused exercises , ensure you have a level of fitness and core strength before getting back on the kite, also building up session times will benefit rather than going nuts ( hard to do) , 100% commitment