I had a non-union on my left collar-bone. Mid shaft, complete separation, unstable. I think I was on my twelfth opinion and several years down the line before it was acknowledged and by that stage I was suffering all sorts of issues. Rotator cuff problems, neck problems, shoulder blade instability. I would lose the vision in one eye at times because of compression of a nerve.
The only purpose physio served was to temporarily help me with the secondary injuries, the pain from the collar bone itself was minor, but I was losing function all over the place which could never be fixed by compensating for a non functioning shoulder. I didn't realise at the time but my life was also dominated by the pain of these secondary issues.
By the time the non-union was accepted in the UK one part of the collar bone was dead and I had to have the lateral end removed and the shoulder reconstructed using an artificial ligament to bridge the gap to a reshaped shoulder blade. Rehabilitation took about ten years, part of this was dealing with problems caused by the initial injury and the period of non-union, part of the rehabilitation was dealing with a shoulder that now worked 'different'.
A few years later I had my right collar bone shattered. Plate and screws - piece of piss. I have very little body fat and I'm quite small so the plate and screws were very prominent. I didn't have a problem with bags and harnesses but occasionally, unavoidably, I would receive a blow on the collar bone which didn't hurt as such but was very, very wrong in a PTSD flashback kind of way. I had the plate removed - even more of a piece of piss. This break wasn't much more hassle for me than a normal collar bone fracture that heals without any problem.