Wow, thank you Colleen. I appreciate you spending the time with that answer because it helps.
If you landed right on the point of your shoulder, you may have stretched or torn the ligament that holds your collar bone to the part of your shoulder blade known as the acromion...called various names (shoulder point injury, AC separation, shoulder separation).....you could have strained or torn your rotator cuff, often gives you problems in raising your arm especially in the first 90 degrees of motion. this usually happens with a rotation or twisting (there's also a lip of cartilage that holds the head of the arm bone in place in the shoulder joint that gets torn sometimes)...not sure how you could do that with the fall, unless your arm got twisted or flailed, or in your fall you partially popped your shoulder out of place and then it went back (fancy name is subluxed)...you really need an exam to tell what you did, but the good news is resting it for awhile and taking anti-inflammatories will do no harm (unless you have asthma or ulcers) so you could try that.But my best advice---see a doctor.
Although I did a standard forward roll, this time I went slower so as to help sensei demonstrate. Without much momentum, I landed on the pointt or just behind the point of my shoulder, but I don't believe I separated the collarbone at all, I'm on Aleve, so I've been trying to move my arm. As I'm doing this, I'm feeling the collarbone(clavicle, right?) and it feels firmly in place.
"... or in your fall you partially popped your shoulder out of place and then it went back (fancy name is subluxed)..."
--this sounds more like what happened.
On asking my sensei, he said put some ice on it and take advil, and that he empathizes. He also immediately tested to see if I could do certain things with my arm and found that I could, so he doesn't seem to think anything was torn but still gave the same advice you did and said he's been there many, many times.
Thanks again Colleen!