ABDOMINAL PAIN ON THE RIGHT HAND SIDE

Hi, when going to bed, I am not in pain. But come morning, the pain is there. I am awoken by the pain on the right hand side. After moving around for a bit, the pain disappers. What is going on? My Dr said it's muscular, put me on Co-codomol but it ain't helping.
On another issue is Mirena, Had it inserted early July 2010, bled 3-4 weeks, stopped for 2 and now it's back. First it's brownish and then bright red. Bleed during the day, come night,.. it stops. Whats going on?