So over the years I have done a lot of damage to my right ankle and as a CNA I am on my feet a lot. Recently I re-injured my ankle. The last time I injured it that if I sprain it again I will need surgery. I made an appointment today after I went to my FCP and she referred me to the orthopedic because she fears I will need the surgery. Well I texted my scheduling manager and told her and she questioned what time it was at and I told her 2 in the afternoon was the only time I could get and I told her I was trying to find someone to cover my shift so I can go and she flat out told me that I would have to come into work after my appointment because shift changes are approved by my boss and my boss said no too. I need this appointment because I don't want my ankle to be getting worse. What do I do? Can they do this?

Go to your appointment and see what can be done for your ankle, and see if the doctor clears you for duty to your job. If he does, then you go to work, if not, then you do as the doctor says. Let your doctor decide what happen next with you, but your boss can demand you work as directed until you have a doctor saying you cannot.

Agreed, telling you to come to work after your appointment is very normal.? You expected the entire day off, if not needed for a doctor?

If as noted, the doctor says you can not work, then you address that issue when and if it happens.