Have you had an ultra sound to rule out kidney stones?
Corn silk, Couchgrass and Marshmallow leaf are probably about the best urinary demulcents as far as herbs go. They soothe the mucous membranes.
Make sure not to use ear plugs as they block the chi to the kidneys. Many people who use ear plugs on a regular basis end up with bladder infections and pyelitis.
Does your urine have a strange odour or any white flakes ? The white flakes can indicate blood in the urine (leukocytes) and may indicate a kidney infection.
Are you drinking enough water to flush your kidneys substantially ?