I have a friend that shattered his collar bone on a fixie. His pant leg that was rolled up and secured became unsecured, rolled down, and got caught in the chain/chainring and he was violently thrown over the bars directly onto his collar bone.
While that is horrible, what happened at the hospital was worse. In spite of the fact that his collar bone was broken in multiple places, everything was pretty much lined up. The doctor prescribed a certain sling to keep things in place, but the nurses gave him a different one that took everything out of alignment.
This is an aside, but it is important. This guy was at one time a VERY strong racer. He was asked to be on an Aussie team by Robbie M back when Robbie was "the man" in the sprints. He was that good.
So being a bike racer at a high level and familiar with that kind of pain he followed his instructions and it totally fubared his collarbone. After multiple surgeries it still isn't right and he is paying for most of this out of pocket because the hospital that f'd him wouldn't admit that they screwed up.
So, my parable is: If you break your collarbone and you think that the medical advice you are getting is wrong, PLEASE get a second opinion.