I "Tend" to think you have a CV joint problem but don't overlook other
possibilities.

One is, in that you had the noise prior to having the rear brakes
rebuilt, that one or both brakes were put together incorrectly BEFORE
they were redone this time.  Then, the mechanic put them back together
the way they were ... which might not have been right.  I know, far
fetched but possible.

Mike