Vibration and Thump Thump noise.

About 12000 miles ago(I am at 56k now) I had my passenger side wheel bearing and both axles replaced due to vibration and noise. Within the last few weeks the vibration and noise have come back. I have took the car in 3 times complaining of the vibration and 2 out of the three times it was blamed on the tires not being balanced. So I paid two places to balance the tires. The vibration is still going on. The last place I took it claimed two guys drove it and could not find a noise. It makes me feel like a doob becuase it shakes so bad on the highway the steering wheel is shaking back and forth, you can see the passenger side seat vibrating and if there is anything in the cupholder it shakes so bad it makes pop bubble. I am guessing it is the wheel bearing again on the other side. Do I just need to go to a dealer? I can't believe I am imagining this.

Thanks.

nate