Suggest Remedy For Sharp Umbilical Pain

I have had 2 episodes of sharp umbilical pain that feels as if it radiates to my vagina today while moving from a sitting/leaning forward position to backward flexion/standing. I am on my cycle now though I have already had one for the month. Took three home pregnancy tests and all were negative. I do use tampons. Do not have a history of severe cramping with menstruation. Could my pain simply be menstrual cramping, tampon related, or worse?