Sorry to hear your having a bit of a setback, same here at almost 6 weeks post op. Sharp, stabbing pain seem to be coming from collarbone area and shoots down to upper chest below collarbone. It's the type of pain where I can't move or breath for about 10 seconds, then it subsides. Muscle spams perhaps?
I think we need to just take is a bit more easy and hope this is just part of the normal healing process.
Best of luck to you, and post if you find anything that helps.
BTW, where did you have your surgery done?