What Are The Side Effects Of Emergency Contraceptive Pills?

I "normally" have mid-cycle spotting. (I've asked my dr about it she said it is normal) Right now I have been spotting (heavier than usual) for almost 2 weeks. The spotting normally lasts about 3 days. This is my 2nd month on a different birth control pill. This pill is similar to the one I was previously taking. Also my hip is extremely sore. I did not do anything to it.