I am getting over brutal cold. On completion of a huge yawn, my left ear suddenly clogged up & can't hear. Already plugged nose&mouth&blew. Suggestions?

Sinus rinse. I would recommend that you rinse your sinuses with something like the neil med sinus rinse kit. The issue with the hearing is likely related to some of your secretions getting into your eustatian tube (it runs from your middle ear to the back of your throat) and middle ear. That should get better with time you could also use decongestants to help (psuedoephedrine).