Suggest Treatment For Pain In The Lower Left Side

I am a 44 year old female with pain in my lower left side. My last three cycles have been 14 days apart lasting two days. I weigh 175 pound and am very active. Along with the pain I have been getting these five minute headaches that come and go. I have no medical history except for having cervical dysplacia and having two healthy children. What could this be. Periods are heavy one day and light the next.