Now that you mention it I remember mentioning it soon after my Mx to the breast surgeon.....who I obviously don't see anymore.....he put his fingers where the pain was/is and said 'well there's no lump there so we'll see".
I have an achey sternum most of the time. On diagnosis they told me that I had mets in the boney part of my chest and upper few ribs....... However I also suffer from reflux and about four years ago (2 years before cancer diagnosis) i was told that this pain was caused by reflux...sometimes it goes through to my back and if I take a deep breath it is painful....sometimes worse thsn others. With hindsight perhaps it was the bone mets, I don't really know....sometimes Gaviscon helps.........could your pain be associated with eating? My other bone mets are in pelvis and skull but they all have remained stable on LETROZOLE for 2 years....for pain relief I took paracetamol and ibrufin, but since just before Christmas GP has told me to stop Ibrufin because reflux has been really bad.......trying to make do with just paracetamol at the moment but it's not brilliant so may go and see him.......he did suggest a stick on patch painkiller but I can't remember what he called it. He has upped my reflux meds as well for 4 weeks to try to get reflux sorted. With our condition we just don't know what is cancer related do we? Hope you get some relief from sternum pain.....if you mention it to medics let me know what they say xx