Can wearing a mask really cause elevated blood co2 level? my bicarbonate level is 33 (my normal jas been 25). a little back pain and shortness of breath, but everything else is normal?

Elevated bicarb level doesn't mean blood CO2 level is higher: they don't test the same thing. Making is very unlikely to raise blood CO2, except maybe in rare cases in persons who already have advanced cardiopulmonary disease whose blood CO2 already is high. Check with your doctor if you have such a problem, e.g. advanced COPD. Otherwise no worry about masking.

Avoid smoke and common allergens. Discuss the possibility of pneumonia, COVID-19 and other pulmonary conditions with your physician. A virtual consult with Healthtap is available. It is important to determine the cause of your shortness of breath. Wearing a mask is recommended if indoors or when you are close to others.