I'm sorry I don't know the correlation of breast bone pain and lymphoma. I would say to ask your oncologist. My husband has terrible pain in his shoulder that they really don't know the cause. They said it's inflammation from the disease itself and offered antiinflammatory and pain meds. Hope you get to the bottom of your pain. Hugs and prayers 🙏🏻
Katie

All my joints are aching since my dx.

Thankyou very much