mid right abdominal dull ache

I started having some mid to mid right abdominal pains during my pregnancy in the 3rd trimester.  My baby is now 4 mos.  The pain was not too bad, and it would come and go.  Now I've had a constant dull ache in my mid (barely to the right) abdomen that I feel all the way through to my back.  I don't notice it being affected by anything (foods, position, etc.).  My blood and urine came back normal.  I have a CT scan on the 27th and an appt. with the GI on the 24th.  I have no other symptoms.  I have a normal appetite, I don't have nausea, etc.  Oh, I am constipated some.  I think that's about it.  Anyone relate?