It could be a lymph node. Sometimes they will be somewhat enlarged and noticeable when our body is doing its part in fighting off illness, germs, etc. Sorry, I'm just a lay person, and don't know all the terminology but this would be my guess.
If it's not painful, try not to mess with it or move it around because that irritates it, if this is what it is. We have lymph nodes all over but more up near our neck, chest, underarm, groin and inner thigh areas. They help our body take care of itself. Maybe help it out with an extra glass or two of water??
Hope this helps and you feel better soon.