Dear Jazmin, welcome to HCM.
With a history of hard hit on the sternum
and persisting pain after 7 months, there is a possibility of a sternal body fracture
An Xray chest AP and Lateral views may show it.
I would advise to see your physician to evaluate for the fracture and any herniation from below it.
You can take some OTC pain killers like acetaminophen
till then2-3 times a day. Avoid activities which promote pain.
Do you get breathless at all?
I hope this answers your query.
Please take care and keep me posted on your progress.