What Causes Lower Abdomen And Back Pains After Insertion Of IUD?

I'm 22 years old and I have one child. When i gave birth I had a ruptured placenta and needed blood tranfusions to get my hemoglobin up to normal numbers. I've had the mirena iud for almost a year now. I have been having the worst lower abdomen and back pains. They're not every day constant but every so often they come back stronger than the time before.. today it hurts to walk, sit, lay down anything. I just started bleeding randomly yesterday after a sharp stabbin like pain hit me..I know some pains come as side effects of the IUD but could it be something else.?