If anything can be said to be nice about this particular traumatic injury (that's a medical term, not a value judgment), it's that it heals fast enough that over the course of a few days I can see the difference. Compared to, say, an adductor strain, that's a novel and welcome experience.

Currently:

• can move my arm straight backwards to full range: uncomfortable but possible
• can abduct it (straight out sideways) to about 20 degrees above vertical (hmm, that's better than yesterday)
• can swing forwards to slightly better than 45 degrees from vertical.
• if I hang onto something such as the top of a door, I can get the arm right above my head.
• as of three days ago I am again able to don a t-shirt without having to hang my hand on the doorhandle. And I can type with both hands again.
• full and very nearly painfree ROM in the neck
• the arm supports the weight of a paper plate loaded with tuna salad

So, things are looking up in general. Most of the painful bit right now is the top of my shoulder/side of neck- guessing this is the trapezius muscle.