thank you for your query.
stretching of the ligaments and muscles of the pelvis often causes pain, stretching and dragging sensation.
Also, during early pregnancy, frequent urination
due to pressure of the uterus
can cause intermittent pain.
Calcium and vitamin D deficiency also could be a cause.
However, this is a very precious pregnancy for you, since it is an IVF conception.
I would advise you not to ignore the slightest pain or warning sign.
Very rarely, pain and cramping could be indicative of an abortion
I am not freaking you out, but if possible, have an earlier check up.