My ears are congested when I sleep lately

I am a side sleeper and when I put my ear on the pillow, it feels like a vacuum seal. So I ended up rolling on my back, which is less comfortable and worse for my sleep. Any suggestions?

See an ENT doctor about potential ear issues.

What you describe isn't normal and I don't know of anything to suggest other than maybe try an oral decongestant (OTC) and see if it helps or not.
I sleep on my side 98% of the time and have for over 12 years on cpap now....never had that happen nor have I read that others have had that happen.
It could be related to some sort of Eustachian tube issue but there are so many and really only something that ENT doc can determine.
I don't like messing with ears and eyes without a doctor's input because God only gave us 2 of each...and once they are screwed up we can't go buy more eyes and ears to replace them.
I don't like to go making WAGs when it comes to eyes and ears.

It's messing with your sleep quality since it forces you to sleep supine and you don't sleep so great on your back....see a doctor.
Anything that messes with our sleep is unwanted and needs to be fixed if at all possible and to fix a problem we first have to identify the problem if at all possible.

My ears have always had more sensitivity than normal - I rarely fly because my ears hurt so badly and often are congested for days after the flight.