What Causes Ovarian Pain And Periods During Nursing?

i'm 31, a mother to 4...my last daughter was born 5 months ago. i'm breastfeeding. starting experiencing a lot of ovarian pain and indestion two months ago....and ended up having my mensus start on the 30th of sept..lasted for 3 days. now again i'm having intense ovarian pain whenever i'm standing....also major indigestion..heartburn where my esophugus feels as it's on fire...had u/s of ovaries 5 weeks ago results showed multiple follicles in ovaries...zantac doesn't remove indigestion problems....and tylenol doesn't do anything either. what could be triggering this?? also when i breastfed my other girls, i never got my period until i stopped nursing...why now???