Marble sized hard lump that does not hurt or move under my left earlobe along my jaw. it's not a cyst or swollen node. no other pain . any ideas?

Examination: Actually a cyst or enlarged lymph gland are very likely causes of such a firm mass below the ear lobe. A physician should examine you and advise you.

Lymph node: This is likely a lymph node. If you don't feel well, if it is over 1 cm in size, if it is growing in size, if it is rock hard or stuck to surrounding structures or if it does not go down in size after a month get it checked out.