Low spO2 breathing awareness at rest

NzBen

I'm a 38 year old male, a little unfit but not significantly overweight. I' e recently got an SPO2 meter back I've loaned to someone several years ago. My SPO2 use to always sit around 97-99%. recently noticed having to take deliberate deep breaths at rest and measured my resting SpO2 at between 92-94%. I have confirmed this reading with another meter. If I take several deep breaths it will go back up to 97-98 fairly quickly.
My BP is a little high, around 130/80 in the morning and 160/95 in evening. I can blow a peak flow meter off the scale. However... I have noticed my lung capacity does not seem to be what Iit once was. With a single breath I cannot blow a balloon to the size I use to... maybe 75%.

Went and saw my doc abt it, she didn't seem too concerned, more concerned with blood pressure. I had a chest xray taken which showed an opacity above my diaphragm between my heart and lung. Which she said is probably nothing, most likely a fat lump. She said we will do an xray again next year and see if its changed.

Now call me a hypochondriac, but i think thats a little cavalier and should have further investigation.

I have never smoked, but have breathed in some bad fumes and dust over the years. And generally in pretty good health. I have had an intermittent cough... maybe a couple times a day for a few months.

Anyone have any thoughts on this? Thanks