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 doesnt reduce and isnt really painful.  I have a very strong abdominus rectus and I cant imagine the compression shorts were tight enough to cause a hernia... Can you tell me what this might be?
There may be inflammation or tearing of muscle sheath muscle starintrauma to peritoneal seat or inflammation of organ need to consult the doctor to find out the cause may see physician till use anti inflammatory tabs ointments muscle relaxants and analgesic so slow protein diet non-oily foods massage rest and physiotherapy is helpful