Welcome to health care magic. 1.The history and location suggest most possible cause could be lymph nodal enlargement, followed by venous pathology. 2.Ths lymph nodal enlargement is seen in any infections / inflammation, localised or systemic conditions and presence of malignancies. 3.I would recommend to get an ultrasound examination done which will differentiate the lymph nodal mass from any vascular , cystic structures. 4.The ultrasound will help to identify the nature of lump,and where it is existing from. An FNAC will give definitive histological diagnosis. 5.You can see your regular physician - the physician would refer according to the findings. Good luck. Hope i have answered your query. Any thing to ask do not hesitate. Thank you.