Pain at the lower abdomen could have attributed by many factors. To isolate the cause of the pain, I suggest you to better see a urologist doctor which likely to request you to have the blood check, KUB x-ray and ultrasound which are the normal procedures for the outpatient. The urologist will make him decide of what treatment is necessary in your case based on those lab. test results.
I have had a full blood count about a month ago for something unrelated which was fine
Usually with kidney stones, there will be blood in your urine, You indicated that your blood test showed no blood in your urine. I would strongly suggest that you seek the professional advice of a physician. The area of your body where you are experiencing this discomfort from could means the discomfort could be coming from a number of possibly serious issues, none of which should just be left to continue unattended. Then again, it could be just nothing. but only a professional can definitely tell you.
The test was just for UTI unless that tests for blood