Do you think you have a blockage because you are constipated? A true blockage usually causes cramping, some nausea etc. And you usually can't even pass any gas.
Regarding your constipation, are you drinking plenty of liquids? If you are and still can't go, you might want to try a gentle stool softener like Colace.
Yogurt is generally good for (everyone's) digestive tract, but I wouldn't think it would help a true blockage.
I suffer with more constipation than I do diarrhea. I use stool softners daily to keep things a little softer and help them pass. It doesn't cause D in me, just helps me to pass the stool.