What Causes Pain In Lower Left Abdomen Radiating To The Back?

Hi: I have lower abdomen pain, but only on the left side. When lying down, the center (not the left anymore) feels a little hard to the touch and it hurts when pressure is applied. Bowel movements relatively normal. No fever apparent. Lately, the pain does radiate on occasion to the left back, left side and left upper leg, manageable with ibuprofen. Both hips and the sacrum were misaligned, treated by a chiropractor last Friday and today (Monday). Thanks.