I have an on and off pain in my left lower front directly behind a hernia scar. It comes and goes and is relieved laying down. Hernia was 30 years ago?

Get it checked out . See a general surgeon for a consultation and physical exam. Could be a recurrence.
Lower abdominal pain. You may have a recurrent hernia or chronic groin pain/strain that hasn't had time to heal or is recurring due to your activities or straining when you void, have a bm with constipation or chronic cough.