Lower left side abdomen pain may be caused by left urinary tract
of sigmoid colon
, left ovarian inflammation
. If you suffer also from chronic constipations and you are more than 50 years old, you are probably suffering from diverticulitis. To treat it, antibiotic intake is necessary (Ciprofloxacine or Rifaximinum for example). After the antibiotics course and one month after symptoms disappearance colonoscopy should be performed.
If you suffer from pain associated with back pain or there are some burnings when urinating, most probable is urinary tract infection. You should have urine tests performed.
Moreover some other abdominal diseases should be ruled out like ectopic pregnancy (pregnancy test should be done) or colorectal cancer
Hope this will help