<s>[INST] I recently ran an ultramarathon and had compression short on during the run.  They were tied and the knot was tucked inside.  After the marathon I noticed that the knot had been pressing on my stomach and caused a bruise.  The bruise is gone now but I have a hard, pea-sized lump on my abdomen now where the knot was.  It doesn't reduce and isn't really painful.  I have a very strong abdominus rectus and I can't imagine the compression shorts were tight enough to cause a hernia... Can you tell me what this might be? [/INST] there may be inflamation or tearing of muscle sheathmuscle starintrauma to peritoneal sheat or inflamation of organneed to consult the doctor to find out the cause may see physiciantill use anti inflamatory tabs ointmentsmuscle relextants andanalgesic soslow protein diet non oily foodsmassage rest and physotherapy is helpful </s>