I am sorry to hear you can feel a lump that is worrying you but I'm afraid no one can tell you what the matter is on this forum.
Lumps and bumps are common and most won't turn out to be anything serious but if they are worrying and don't settle after a short while they are best checked out by a doctor just to be on the safe side.
See how things go over the next week or so and if it is still there or you notice any other symptoms then speak to your surgery to arrange an appointment.
