Do work limitations, (example - a doctor's note given to an employer stating that the employee cannot work anything overhead) fall under the HIPAA laws? An incident happened where a list of everyone's work limitations fell into another employee's hands to read. Did that employee who read this list have the right to even read it?

This has nothing to do with HIPAA; HIPAA is a violation of personal information such as medical records, social insurance numbers, hospital numbers, etc.