Most likely those lumps are lymph nodes which may be swollen due to a number of things.  I've noticed myself having a swollen node around my ear once before when I was sick with a horrible head cold.  I made note of it to ask my doctor on my visit the following week, but by time my appointment came the node had disappearred.  When you mom had her mastectomy, did they check the lymph nodes under her arm for evidence of the cancer spreading?  If the pathology showed mastisis, then there would be a definite cause for concern.  However if she's had any kind treatment or illness it's possible the nodes are just swollen and will go down on their own.  If they haven't reduced in size within a week, or if they get any larger then I would consult with the doctor.

Good luck!

Angi