What causes lower back pain and lower abdominal pain on the left side?

Answer

If the pain is constant and/or you are running a temperature, give your doctor a call. There really isn't anyway to diagnose on a website.
gullbladder infection
For start of, its GALLBLADDER. And second its not. I had mine taken out YEARS ago when I was quite young & I had a uterine iunfection recently and everytime I eat now, I get severe lower back pain and a pain in my left rib...could be to do with the kidneys am still investigating.! The gallbladder is on the RIGHT hand side of your body by the way!! Well, I had pain on my left side, near the spleen. I don't know what it is yet... I don't know if it's spleen or any other organ... on my left.
Your pain could be a urinary tract infection. Consult your doctor to be sure.