Ugh, bowel blockage is no good! How did you know? You had severe pain and nausea? My son had a bowel blockage of his own feces due to being severely constipated. He wasn't hospitalized though, he was treated in the ER. An ER confirmed the bowel was completely blocked and it was his own waste doing it. Now THAT is sever constipation! They gave him an enema. He also was instructed to drink a cup of red or really purple grape juice every day and eat fruit. He takes a probiotic smoothie regularly. (I buy the premade ones by activa in the dairy aisle). Staying hydrated really helps as well. Think of your large intestines as a giant water slide. You need the liquid/water to move the rides (poop) down the slide. Not to be too gross. sorry.
So, the idea of acid reflux is new for you? Antacids are pretty benign and harmless BUT they can cause constipation! My best weapon against GERD is lifestyle management. Keeping my weight optimal (having to lose some), eating a healthy diet, avoiding some things (spaghetti sauce causes reflux for me as it is very acidic and carbonated pop), don't eat too close to bed, drink plenty of water, eat fiber, etc.
I don't know of a correlation of gerd and constipation. I think they are two thins you will have to work on separately. But, you'll have to be careful. That you already have constipation, you need to make sure if you take a medication for GERD that it doesn't add to it.
What did they do to treat the blockage in the hospital? Did you have a tube to empty stomach? What did they feel the blockage was?