Hi welcome to Health care magic forum.
Thanks for choosing H.C.M.F.
As you describe Since 2 days you had pain in the lower abdomen, remission when you lie down. No tenderness to touch.
The description is not clear, if pain is on right side it may be urinary tract infection
, or kidney
stones or chronic appendicitis
. if to the left, urinary tract infection, or stones, if to the center, may be of urinary tract infection, or stone in the bladder.
I advise you to consult a surgeon for diagnosis and treatment. You may have to go for U.S.scanning besides other routine tests for confirmation.
Wishing for a quick recovery.