Trying to make me miss physio.

I recently injured my right shoulder, not overly badly but enough that I was directed to get into physio. This kind of sucked because it happened to overlap with my vacation. But whatever. My sessions are on thursdays at 1:00PM, so 1: I have to miss work and 2: afterwards my shoulder is in quite a lot of pain and I can't return to work. Usually icing it afterward.

My condition is week to week, not eligible for disability and honestly, I don't want it. I've been simply asking for Thursday's off and picking up an extra shift over the weekend to compensate.

Problem is, because i'm "Full time" I'm not entitled to have any days off in any form of consistency. They say i have to be on disability for that to work. They keep pushing me to sign off on a "Adjusted work form." Which i can't get my therapist to sign because my condition is improving. This thursday is my last session, if all goes well I should be off physio, but if not I'll be put in again next week. Problem is, my boss is telling me I can't go because he needs me to work.

Is it normal for him to do this? To me it seems like he's putting a stupid schedule over the health of his employees.