Abdominal pains during an early pregnancy are similar to the ones experienced day or two before and during first days of menstrual bleeding.
Lower left abdominal pain can be related with bowels function and pain from the bowel is often described as colicky in nature. This means that the pain or discomfort comes in waves with little or no discomfort in between the pain.
You may have constipation, irritable bowel syndrome, diverticulitis.
Also, it can be related to your gynecological system, like uterus, tubes and ovaries.
Sometimes, left lower abdominal pain is a sign of ectopic pregnancy.

According to the character of your pain, I think it is originating from your bowels.

Best wishes!