How are you? It is good that the initial diagnostic tests were fine. Frequent urination may be attributed to infection, disease or injury of the bladder, or from conditions that increase urine production, changes in muscles, nerves or other tissues affecting bladder function, and even malignancies. If it persists, further evaluation as well as additional diagnostic tests may be done. A referral to a urologist may also help rule out other issues present. Take care and do keep us posted.