Hi, Around 10 - 11 Months Ago I Found An

Hi, around 10 - 11 months ago I found an enlarged lymph node in the right side of my groin, the weirdest thing is it changes shapes and sizes depending on how I have my leg positioned, very odd, but anyway it is 2cm EXACTLEY, and hasn't got any longer at all, it's been this way since I found it, I've been to 3 different doctors who said they cant find anything wrong with it, and they've also said they cant find any hot spots in it? apparently they are looking for "hot spots" in cancerous lymph nodes, is this true? it hasn't changed size at all.... but next to it around 2cm's away, I am sure another lymph node is maybe growing :S, it is the size of a pea on one end, but its like its attached to a tail maybe? a long thin matchstick type shape is as good as I can describe it, but underneath that "what I believe to be a 2nd lymph node" there is like a pulse, I can feel it beating, is this a bad sign? I am wondering whether to go back to the doctors, I am very worried.... im 24 years old, very sporty, I sprint 3 days a week, I weight lift every day, I train muay thai and mma every day, so I am constantly being slammed around, all of this lymph node stuff started 11 months ago when I had a very bad pain in the exact area of the first lymph node, which my girlfriend advised to go see a doctor, so I did thinking it would be a hernia and he goes "that is a swollen lymph node" and he marked it down to sport related injury, but its been 11 months it has not gone down at all, it has not grown "maybe a little in width" but nothing at all in length, I am worried about both nodes, "assuming the 2nd node is a lymph node" as im sure lymph nodes don't pulsate? please get back to me ASAP I am shitting bricks, thanks