I didn't have that actual sound that I recall, but I had all kinds of crazy noises in my ear last summer. It has lessened a lot (maybe b/c of a few rounds of steroids giving some temporary relief). I also wear an earplug in that ear if I'm going to be in a very noisy environment so I don't have to hear echoes of it for hours afterward.
At some point I had to tell myself not to freak over every new symptom. (Not to say that you're freaking -- I was. When I started having a tingling, numb scalp one day? I was calling relatives in a panic thinking I'd wind up in emergency brain sugery that very night!)
I would keep track of symptoms and tell your doctor, but I find they are not too excited about new symptoms once they have already diagnosed you and it's an expected symptom that fits the profile, you know what I mean? Like when you say "my ear is popping," s/he'll say, "yes, you have an inner ear tumor."
I have definitely found that cold/sinus exacerbates things. Insults that a healthy inner ear could accommodate for, it no longer can.
ETA: Now that I think about it, I might have a Rice Krispie type of noise. I call it crackling ("snap, crackle, pop," after all). I do not have popcorn noise.
