You could consider going on the Pill, which regulates your hormones so that you do not ovulate. No ovulation = no 'period' so to speak, instead you will get what is known as a 'withdrawl' bleed once a month.
Basically the same thing, but the big difference is that it is often lighter, shorter, and much less painful!
Talk to your doctor and/or mum to properly decide if this option is right for you. Other benefits are protection from pregnancy and sometimes clearer skin.
Other than that, there are many over-the-counter drugs specially prescribed for period pain, have they not helped?