My 21 year old daughter experiences immense pain during her menstrual cycle. it is also very irregular, she'll not have it for a few months and then get it for a week where she can't move from the pain. what action would you suggest?

Have her evaluated: The original research on the pill was directed at controlling symptoms like you mention. After several years the birth control side effect became it's more common use. If she will seek out an evaluation for these issues this could be a simple fix. It may take some trials on one or more to reach a good fit for her but life could get much better with something we've used for decades.