There may not be a way to tell without video, but I don't always land on my shoulder.

Also, I have been training judo for 2 years (with 3 years of BJJ in childhood.) I am a grown adult.

I don't land on my shoulder. Only with some Toris. My shoulder hurts and I chose to not attend class today because of this.

Is the issue usually that Tori doesn't rotate Uke enough or is there also something Uke can do in order to not land directly on the shoulder?

Also, I find that, ocassionally, the timing of my breakfall slap is off. The slap should be a split moment after landing, no?

I'm probably going to take a rest until the pain goes away. In the meantime, I'll just be practicing Tai Sabaki and ukemi.