Can indigestion/acid reflux cause chest tightness & feeling like I cant take a deep breath/shortness of breath?

Unlikely . It's possible, but much less likely than other causes. In general, the chest pain you describe in your age group is more likely to be musculoskeletal (strain or inflammation) or respiratory (viral pneumonia, bronchitis, asthma). However, it could be cardiac or even GI related. You should contact your doctor immediately or go to the closest urgent care/ER if you're having breathing problems.