Oh man, I had it in right ear too for some weeks or maybe even months. Got quite worried already but then it somehow solved itself. Just in case I'm now always extra careful with loud stuff, and for example in cinema I often have earphones on because goddamn some movies are loud.
I'm pretty sure this is happening as a side effect to a medication, so hopefully it will pass in time. If not, I might have to try some things. It's very mild, but it's enough to concern me as it was never there before.