Thanks for using this forum. As per your description this seems to be more towards a swollen lymph
node which are usually present in that area. However you also have to look out for other symptoms such as any pain/discharge from ear, any upper respiratory infection
or any condition in the region of the head. Usually any infection in these parts would lead to this. Other condition nearest like you said can be cysts but usually they are not very painful, if they have not become infected. You should consult with your GP and seek further advise if the symptoms continue. Post in for further queries. Regards.