I can use a CPAP machine during the day and I feel out of breath but my PULSOX is 99%. Is this possible?.

I say that I am missing of breath, because I am out of breath and hufffing and blowing. I do not know if this feeling is in my head.

Do you have any anxiety problem? It sounds like you deconditioning and the need for the activity questions oxygenation. See your doctor for additional questions. I hope you feel better soon, God bless.