What Causes Ear Blockage In Supine Position

a few days now, when I sleep on my right side my ear feel like it gets clogged and can't hear out of it. When I sit up, it takes a few minutes but it clears up and doesn't hurt or anything. I don't have a cold or anything, no itching, I'm not sure if I should go to the dr or just give it time to see if gets worse/starts hurting....what do u think?