Had a sharp pain in back going down stairs my legs gave out and i fell and slide down on my back, i have really bad back pain and my back feels bruised but no bruise i have needles and pins in back and down leg into foot could it be a slip disc?

Could be multilevel contusions/sprains & strains from falling down the stairs and bruising the back. While basic first aids like alternating warm & cold compresses, & taking OTC analgesics like Panadol/Tylenol or even Ibuprofen can help, it's best to see the PCP soonest so that if preventive care- like Back Bracing, neck stabilization or Shoulder bracing are indicated one can have it with imaging