I have been searching for the similar SOB problem for years and am glad to come across this post today. I first had this deep breath needing issue 20 years ago. No clear medical issues were found at that time. The issue was gone a few months later but came back in recent years. The issue is especially worse (have to take many deep breaths) after full meals so I suspect it is also related to acid reflux. Overall my symptom is not super bad so I didn't see a doctor for this recently. Two years ago my daughter (born in 2009) started to have this same issue. She needs deep breathing (sighing heavily) from time to time even without doing any exercise. She is a soccer player and the need to take many deep breaths in a game caused a big trouble to her. If some of the deep breaths didn't go through well, she started to get panic and struggle to get more deep breaths. We are very serious about her soccer but now the breathing issue is already affecting her performance badly. I recent took her to see a doctor (didn't do this earlier due to the pandemic) and so far all the tests are normal. She has excessive belching issue (but no severe heartburns) so I suspect the breathing issue was due to the acid reflux too. I gave her TUMS gas relief pills but it didn't seem helpful (did about one week). Probably I will try Prilosec and the Buteyko breathing exercise that Gabe mentioned in the post. If anyone has other suggestions please let me know. Very appreciate it.