From your description, you seem to be having a bad reaction to the polluted air, causing you to have non-infectious bronchitis and/or pneumonia, the normal pulse oximetry notwithstanding. It appears also that, with the bronchitis, you are having significant bronchospasm, as a person with asthma might. You should have a chest x-ray for if you have pneumonia, you will need more intensive therapy. You could also have a condition called bronchiolitis and that too would require the use of more intensive medicine, including oral steroid medicine.
Regardless of what the x-ray shows you could benefit from the type of inhaled medicine used to treat people with asthma.
For the time being, you should avoid exercise, especially outdoor exercise. You should stay indoors, be it at home or work with air-conditioning, and go outdoors only when absolutely necessary. You should also ask your doctor to prescribe a mask to filter out particulate matter in the air.
Finally, if there is any way to reduce your exposure by going to a less polluted part of the state, for a while, you should do it. If your condition worsens, you may have to see a lung specialist and, if you do, ask him/her about the above advice.
I should add elaborate a bit and say that the feeling of resistance while breathing in was initially a problem at night, then during both night and day, and now mostly at night, with some periods of relief. In other words, it's fluctuating.