Please go through this and see if something was missed . Pain
and discomfort on the lower left side
of abdomen just below and to the left
of navel can be due to several causes such as Crohn’s disease, diverticulitis, infection in kidney, kidney stones, constipation (this you do not have), and an abscess in rectus abdominis muscle or psoas muscle. Since you do not have a lump or a tender hot spot, in all probability it is not a muscle.