It is really demotivating to see juniors as getting more pay

I am Tgt science in a reputed school. I got promoted for the post in the year 2005 after there was a vacancy for the post. My basic as on 1.01.2006 was 5,500-175-9000. But junior who joined the school after 1.04.2006 and years after are drawing more salary about 3000 more than me. Is this possible? What should be the correct procedure to calculate my pay. Its really demotivating when u see thm more than u after least contribution towrds the development of our schl.I hve heard thro sources that thr shd be some step up sal so tht we wd be draing the same though not lesser thn thm.I wd be extremely tahnkful if u cd guide me at the earliest on ths.
P. Gayatri