Does anyone know why sometimes I feel wheezy when I breathe, (it's scary but not actually hard to breathe)?

Background: My doctor has diagnosed me with stomach acid problems, probably caused by my panic disorder, which has improved a TON since I was diagnosed. I'm taking Omeprazole for my stomach. This wheezing SEEMS to happen in conjunction with sitting all crunched up in my seat or laying down in bed - when I sit up straight, it seems to go away. Has anyone else experienced this? Should I be worried?