while sitting and waiting at a stop light the light finally turns green and as I get ready to proceed forward "BAM" the car behind slams into me. Since the light had just turned green I had barely just started to move my foot towards the acellarator very patiently ,seeing that the traffic was backed up quiet heavely (approx.4:30p.m) I knew to be calm, take my time and prepare to proceed with patience. The driver of the car did express to me that she did'nt pay attention, that it was her fault because as soon as she saw the light green she assumed I was impatiently and quickly proceeding forward as well. I ask for her D/L, and her insurance info. I took down all the info I thought was important.For the last few days now I've been having severe lower back pain What should I do ??