I am a 23 year old female, with a lump on
my upper left side of the abdomen
, right under my ribcage. The lump is only there sometimes, it will tighten into a hard long lump, then I stretch out and rub it lightly and it goes away. It comes if I turn awkwardly, sneeze, cough too hard, or exercise. I have had this happen randomly since I was 11 years old. The spot where the lump formed is always tender afterwards, for a few hours... but the lump is no longer there, just the soreness.