I recommend contacting the dr. who had the tubes inserted. I had tubes twice as a child due to frequent ear infections. To my knowledge, their purpose is to widen the ear canals to promote good drainage from the ears. So I would surmise at this point, either the tube on the left has worked its way out or is no longer fulfilling its designed purpose.
I had a situation once when I had my tubes the 2nd time. I fell in the pool and got my ears wet, which was a no-no. I think it may have been after this I got an ear infection and the dr. who had put in my tubes- every time I saw him, he'd look in my ears and say "Beautiful, beatiful" but when one of my ears was hurting so bad and blood was trickling from it, a different dr. said they didn't know how that dr. could say that with all the wax in that one ear. They treated the infection first, then had the wax vacuumed out of my ear, which I recall was VERY noisy.