Welcome to Health care magic. 1.As per your history i felt like lipoma initially but as you said increased in size and pain causes suspicion. 2.Most possible cause in that location would be lymph nodal enlargement followed by lipomas and vascular causes. 3.To confirm the diagnosis - you need to get an ultrasound examination done. 4.Ultrasound will help ti evaluate the nature of the lump, its source and where all its extended.If required a needle sample will be take for confirmation of the cells. 5.So get an appointment and get needful investigations and treatment done. Good luck. Hope it helps you. Wish you a good health. Anything to ask ? do not hesitate. Thank you.