Hi,Welcome with your query to HCM virtual Clinic.
I reviewed all the details of your query,in context of the of the painless hard lump below right collar bone.
Based on the facts of your query,You seem to have Costochondral joint-mostly as the lump is hard.
You don't have history of any recent viral/bacterial infection in the area around it and hence no question of it being
lymphadenitis there.
Being athletic,the only possibility is Costo-chondral joint lump near breast bone,which is a normal elevation like hard lump and hence you should not worry unless it gives more trouble to you.
USG study of the painless lump below collar bone medially near by breast bone,would resolve this worried lump issue.
Hope this reply would help you to plan treatment with your doctors and resolve your worries.
Will appreciate writing excellent review comments to help the needy patient visitors like you at HCM.
Welcome any further query and information in this regard.
Good Day!!
Dr.Savaskar M.N.
M.S.Genl-CVTS