Talking to my surgeon this morning, I received confirmation that it is indeed my clavicle plate pushing outwards on the skin and easily felt. Why? Because I would have been perfect for a medium-sized plate - but they only make them in two sizes. The smaller one wouldn't have fit at all and would not have secured the big break properly.
After it's healed (a year), I will wait 6-9 months and the surgeon will go in (hopefully by the same incision) and remove the plate. Some loss of sensitivity on the skin, but I'll take that for not having my skin possibly ruptured if I fall slightly, or having a permanent bruise - from the inside. (Think as skin loses more elasticity in ten or twenty years.)
I'm okay with that.
Some testimonials support this view and indicate recovery is within two months. May not even need physio. Woo.