Why i feel a pain or sore in my for almost a week..what is this cause pls.help me?

as i said first since i stop my pills for 17 months...my period become irregular.we used a withdrawal method.apr.27,start my period,then nxt june 2,then july 1..then untill now,im expecting my period for this month..and i wanna know what i feel sore around my for almost a week...eventhough i had a negative test,without any faint line..a clear oneline..im 38 yrs.old i dont think im not getting menopause..all i wanna know what is this sore around my please help me..