Such kind of chronic groin pain can be due to kidney disease like kidney stones, glomerulonephritis, inguinal hernia, nephritis, osteoarthritis and urinary system causes.
In my opinion, investigations like kidney functions, blood sugar levels, ultrasound lower abdomen ,intravenous pyelography ,prostate specific antigen blood test and cystoscopy may be needed to confirm a diagnosis. I sincerely advise you to consult a urologist or nephrologist and get yourself evaluated so that a confirmatory diagnosis can be made.
I hope it helps. Take care and regards.