Exactly!! The surgeon told me separating the sternum and essentially disrupting the ribcage can cause this pain. It's muscle pain, but boy it feels worse. No, I didn't take medication either just dealt with it for a few weeks until I got stronger and now at 4 months no issues.I had similar intercostal pain. It is not surprising that the intercostals would experience some strain, given how the ribs are pried open after the sternal cut. For me, the intercostal pain was not severe enough to warrant pain medication, but it was annoying. If memory serves, I started feeling some of this pain about 6 weeks after surgery. It lasted about 2 weeks, but then another intercostal would start to bother me. I'd say by about 4 months out this was no longer an issue for me.