I have the paraguard as well, and like you I never had any problems with periods before. It was exceptionally painful and the periods lasted a long time (7-8 days) and sometimes had the "afterthought" bleeding - as in I thought I was done after 6 days but wasn't quite done.

That was 4.5 years ago, and eventually it does stabilize. My cramps are back to just being a nuisance, and the bleeding's no worse than what it was before and back down to 6 days.

Not sure what you can do to curb the pain other than the OTC stuff and waiting it out, but it's a good idea to get it checked to see if it's still in the right place.