Fell in Giant paarking lot on Friday - did not have any pain or issues until next day - is it too late to do anything about this issue.

It is not too late to seek legal recouse against Giant for your slip and fall.  Maryland has a three-year statute of limitations.  You should immediately seek medical treatment for the injuries.  It would be helpful if the doctor could, in the medical records, rule out any cause other than the slip and fall.  Keep copies of your medical bills, and keep a diary of the pain and suffering you are experiencing.  Afterwards, you should immediately contact a personal injury attorney in Baltimore, Maryland.  My firm can help if the slip and fall occurred in Maryland.