Im dealing with the same case but not with squats....there is some lower back pain but its mainly with deadlifts. Its been about 3 weeks since it happened. I got a really bad pump after 1 set and i stopped and rested it not doing much lower back exercises. Ive taken Taurine as suggested about 3-4 grams/per and using a belt more often. Only loss is a decrease in strength with deadlifts about 20lbs.