I recently began squatting and have had pain in my lower back. I am wondering if this is something that is normal when you first start this exercise (I doubt it). I am guessing it is my form or something structural (my back hurts where it did when I was rear ended in a car accident a number of years ago). Questions are 1) Is this normal? 2) Can I do other exercises to replace it that which will be as effective? I know I can use the leg press. Currently doing 5X5 program. Thanks for any help.