The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
Something in your training is giving you sensitivity in flexion. It’s either something you are doing too much of or not enough of. Low back pain is never an isolated incident it is typically an accumulation of many factors. It is never as easy as “where should I stretch or put the lacrosse ball?” I suggest getting an evaluation by a PT in your area, check the MWOD list, who can do a thorough history and exam of you specific pain triggers and help you develop a plan. Until then it is best to stay out of the flexed positions which are aggravating you as best you can to desensitize the movements to the pain response and work your back in positions that don’t aggravate it. This is also a good time to add in farmers carries or suitcase carries (just holding one heavy dumbbell) to start working your spine in the frontal plane.