I Have A Lump Just Below My Xp. It Sometimes

I have a lump just below my xp. It sometimes is sore but usually goes away after a while but the lump stays no matter what. A doctor at a walk in clinic says its a xiphy sternum? And said its my xiphoyd has flipped out and not in. My concern is that the lump is hard and doesn't seem to be going away. Any help?