lumber disc protusion

i was recently involved in an rta..i was in a stationary car when i was hit at significant speed in the rear end by another car..i have never suffered any back problems before,but since the accident ive had severe back pain in my lower spine..i have been having physio for the last 6 months with no improvement in the condition,i went for a medical and the doctor suggested an mri scan..this has comeback with disc protusions in the lumber vertebrae,the doctor who assesed the mri scan is not a back specalist so he cant accertain if the disc protusion was caused by the accident(what else could have caused it) i have now been refered to a back specalist for his prognosis..what i would like to know is what is the long term implications of this back injury,and what sort of figure should i be accepting in the form of compensation..any information anyone can offer would be most appreciated..many thanks michael..