Thank you all for the responses.
Hi
Welcome to the MedHelp forum!
Groin pain can occur due to several causes like swollen lymphnodes, hernia, kidney stones, inflammation of large and small intestine and muscle pull. Apart from these it can also be a pinched nerve. Since you had a small lump it can either be swollen lymphnodes or neurofibromas. Swollen lymph nodes in the groin could be due to STDs (e.g., gonococcal infection, herpes simplex virus, syphilis, chancroid, granuloma inguinale, lymphogranuloma venereum etc), infection in foot, dermatitis in pelvic area, boils in pelvic area etc.
Since I cannot examine you and know other related conditions you may be having, nor is a detailed history possible on net, I have listed the various possibilities that should be looked into. Please consult your PCP for primary examination followed by proper referral.
Take care!
It sounds like you are tight in your psoas and/or iliopsoas muscles, although it is not easy to distinguish this problem from a hernia. Sitting too much is one of the risk factors for the tight muscles, and if you don't learn to keep these stretched out, you can easily get serious groin pulls and other muscle problems that take a lot of time to heal. See a doctor to make sure it's not a hernia though.