We are not talking about disc damage.
the guy is talking about his lower back pains. could be disc or nerve. regardless it's probably gonna be associated with the area around his spine.
reason im so adament about this is bc i messed up my lower back with the boxes and saw a dr. regarding it. Specifically said that the box squat is more likely to wreck havoc on the lower back because when your ass hits the box and has nowhere to go, and that weight is pushing from above, the point of stress is now your lower back. With reg. squats, there is no box involved that would cause such compression.
hope this helps.
for the author of the thread too-->try some heavy, high rep leg presses ..sets of 20-30