^^^ Yeah, if you haven't got a pipeline into your body and how it's dealing with stuff a broken bone will certainly guide the way. If it hurts and still flexes don't strain it. If it feels OK it probably is OK. The join where the bone heals is (like a baby's skull) flexible and really kind of tough. After it fully fuses it is bomb proof. Lumpy but bomb proof. You'll break the process or your sternum before you re-break that scar...
What I didn't expect and was uncomfortable for a few days was the re-alignment of my back muscles to the change in my shoulder width. Actually turned out good for my driving golf swing. I didn't slice nearly so bad.