I Have Had Severe Pain In My Midsection At About

I have had severe pain in my midsection at about belly button height for about 2-3 years now and sometimes it's so bad I cry. It happens about every 3 or 4 days, sometimes for like 20 minutes, sometimes hours. I'm not sure if it's relevant but I had a kidney infection a few years ago. Although, it's not the same as period cramps. Also, I'm a 17 year old female and I'm starting to get really worried about it but everytime I go to the doctor I forget to mention it. It wakes me up in the morning and stops me from sleeping and it sucks. Please help