What Causes A Small Knot On The Groin Area?

I noticed a small hardened pebble when I was about 12 years old. I never got it checked out until I started having severe pain in my testicles and groin area, which happened around 19 years of age. My doctors conclusion was that it was a calcium deposit and he had a scientific name for it which started with a V. Ultimately though I was told not to worry about it. However since the age of 12 til now at 29 years of age, the pebble has grown in size to atleast the size of an eminem, for lack of a better example. If it was correctly diagnosed as a calcium deposit, should it have grown through the years? Thanks very much, this is very important as I deal with debilitating groin pain on a daily basis. Thanks for you for your concern in advance.