What Causes Pulsation In Clitoris Post Intake Of Birth Control Pills?

Hello- Recently I began new birth contr (3 months ago). Since then, my clitoris has been pulsating (usually at night). This is very stressful and I cannot figure out why it is happening. I stopped my birth control two weeks ago(after I finished month 3) but it has not stopped. I have had one partner for the past year and am clean. What could be causing this?