My Primary Question Is 'are Fluctuating Oxygen Levels Normal?' Two

My primary question is 'are fluctuating oxygen levels normal?' Two months ago, both lungs partially collapsed during a laproscopic abdominal surgery. I have since had 4 infections, but not in my lungs or surgery site, and my immunity is low. My heart rate has increased, and I now have high blood pressure for the first time in my life. I use 2L of oxygen at night. My oxygen levels fluctuate consistently, dipping as low as 55, but within a minute, my oxygen levels return to 90's. I check my oxygen frequently with an oximeter and this happens most every time I move and sometimes when I am sitting and nonactive.