Can I get paid for my out of pocket expenses, sick time and medications for a back injury and surgery secondary to work injury 3 years ago?

I assume from the facts given that your accident happened in Florida and therefore is governed by Florida workers' compensation laws.  Under Florida law, you generally cannot recover payments made for out-of-pocket medical expenses related to a work injury unless the medical treatment was a true emergency.  You should have contacted your employer or its workers' compensation insurance carrier when you determined that the hernia was work related and asked that it be covered under workers' compensation medical.  By going out on your own and using your private insurance to pay for the surgery and then paying on your own for the medications without first seeking approval from the workers' compensation insurance carrier, you unfortunately likely forfeited your right to be reimbursed for these expenses.