Discuss pain with MD. Fibroids should only be treated if they are causing significant symptoms. If the pain is only once and a while and is manageable it doesn't warrant treatment. However, you should discuss these symptoms with your doctor to make sure that the pain is due to fibroids. This is usually done with a thorough history (about the pain), physical exam, and a pelvic ultrasound.
Depends. Fibroids are just one of the causes of pelvic pain. Typically the larger the fibroid the higher the chance it can cause pain. Also location of the fibroid is important - if pushing on the pelvic bones or sacrum. In order to see if your fibroids are causing your pain you do need to be examined and have at least an ultrasound to examine the size and location of your fibroids.
Probably not. Fibroids are not cancers and do not turn into cancers. They are a nuisance and can cause a lot of problems but, as the old story goes, if it ain't broke, don't fix it. So, to answer your question, if you are only having problems occasionally, you don't have to do anything if you don't won't to. If the fibroids are affecting your life negatively, then you might want to seek further therapy.