I've posted on this site some years ago and I wasn't really intending to start a thread. I just wanted to share my experience with the rest of the world, because now I believe that exercise is key for acid reflux (and unguided exercise is the cause of my gerd).
I am pretty sure now that I damaged my diaphragm while weight lifting in 2001 (then I was 21 and completely healthy). Since they I was stupid enough to do Judo for 1.5 yrs, until stabbing chest pains DURING practice convinced me to leave the sport.
After that I played some recreational soccer, because I believed it was lighter... and then LPR began! That made me VERY sensitive to reflux (as opposed to before when I would only feel the burn couple of days after exercise and couldn't correlate the two). With LPR I could feel it start as soon as I began working out. I felt terrible with my throat being burned and I also considered surgery, but my doctor is completely against it (because there are no good lasting results apparently).
Now that I've been exercising very little, very lightly and by following these rules, I don't feel LPR and I barely feel any GERD (thank god). My motivation for avoiding diaphragm exercises is that its connected to the stomach and hiatal hernia of the diaphragm is the cause of reflux for some people. The motivation for not changing level and staying vertically upwards is because the cause of GERD is that the stomach doesn't close at the top. So your goal becomes similar to carrying water in a cup without spilling it. Finally, a lot of reflux is caused by stomach spasms, which become more frequent with physical/emotional stress, so I avoid intense exercise.
As a side note, I found this regarding your polyps (doesn't seem like its anything to be concerned about).
Can I ask how old you are and what PPIs you've taken, and do you have H Pylori (I assume you are female)?