I'm 18, and started menstruating when I was about 12. They were mostly regular and were regular for a couple years. But for the past 3 years I've had very irregular periods that come 2-3 months apart and even sometimes happen every month. They are very irregular. AND I only have cramping or pain in my left side. Even my back pain! It's ALL on the left side. I've had ultra sounds but nothing came out of it. My doctor seemed to think it was ovarian cysts since I am prone to cysts in my breasts. Is this normal? What should I do? I'm very concerned about my chance of having children in the future.