Yes if you are sitting up you can hold tummy and lean over.
Yes it is painful due to the ligaments being stretched. Hold ure lower tummy and sit up when sneezing. It helps me a lot and the pressure is less as well. I hvnt tried curling up my knees as suggested by @bnl0725 will definitely try if it helps :)
It's your ligaments pulling. Hurts so bad too. I curl my knees towards my belly before I sneeze. It helps.