A few weeks ago I was at the tail end of a bad cold. I felt 90% better, but still had a few sniffles.
A friend of mine and I took an Arrow up to 11,000 on an IFR cross country. On arrival, descending through 6,000 my right ear started to feel plugged. I yawned and it didn't pop like usual. Passing through 5,000, it started to ache a little. Passing through 3,000, it was killing me. I was just thankful my friend was flying that leg. The pain went away within 30 minutes of landing, but I couldn't hear out of it until the next morning, no matter how much yawning and gum chewing I tried.
Made me realize that head colds and night IFR don't mix. I wouldn't want to experience that if I was solo, in the clouds, trying to shoot an unfamiliar approach.