If you're worried about stones, you might want to get an ultrasound - which can spot larger stones, or go for a CT scan (which can also show diverticular pockets and other physical or structural indications for why you may the pain.
A quick glance at descriptions and possible causes for LLQ abdominal (Left Lower Quadrant) pain include the following (they're not meant to freak you out! - but it sounds like you should follow up with your GP if this is still worrying you):
Symptoms - Pain in the back that usually spreads under the rib cage, around the front, and into the groin.
Causes - Kidney stones
Suggestions- See a doctor promptly
Symptoms - Extremely sharp abdominal pain, perhaps with other acute symptoms.
Causes - Pelvic inflammatory disease,Heart attack,Perforated stomach ulcer,Shock from allergy,Diabetic emergency,Poisoning
Symptoms - If you experience pain in the lower left abdomen, and often sudden, severe, and located, along with fever. You may also have nausea, vomiting, chills, Abdominal tenderness. Your bowel habits may also get changed, and either diarrhea or constipation.
Causes - Diverticulitis
Suggestions - You need to make an appointment with your doctor immediately if you have sharp abdominal pain in left side along with fever, chills, swelling, or nausea and vomiting, go for emergency treatment right away. You may have peritonitis, a life-threatening infection of the abdominal cavity.