For the manual therapy, the therapist did not explain in a lot of detail what he was going do but he did say he was going to work on my neck and that the muscles seemed quite tense. I don't think he did anything sketchy per se, it felt intense (but not painful or alarming) during the massage but I thought that was normal because the massage is supposed to release the muscles.

I do not think that was the problem as I also felt fine during the massage. If not I would have said so to him immediately. But right after the therapy was over I started to feel off but by then it was too late ...