I am 19, I have a pea size lump just to the left of my right hip (Near groin). Was black and blue, but has gone away. Hurts now and then. What is this?

Hematoma ? bruise, or cyst that burst , did you have a trauma there recent , body absorbed it likely , if comes back or pain see your dr . could have been a lymph node due to some inflammation but if any penile dishcharge or anything related to testes or scrotum might be std or hernia.
Sounds like a. lymph node.. and by its location the most common source are the feet...small cracks between toes, athlete's foot (fungal infection) etc. Get it checked out by your Primary Care Provider (Family Doctor, Internist etc) Hope this helps! Dr Z.