My last period I had a dull pain on th right side b4 it started then no pain during which is unusual for me?

Pain around period. Pain just prior to your period can be a sign of an ovarian cyst but this depends on when the pain is relative to the onset of bleeding. Depending on your age it is not unusual for your periods to change (become more frequent or less frequent, or to have cramps get more severe or less severe). It is always prudent to be sure you are not pregnant by doing a pregnancy test.