I have been studying chronic pain in detail recently.  It struck me how similar chronic pain and tinnitus are in terms of how the mechanisms may work.  Both are related to dysfunction in the nervous system and specifically in how they are both hyper-sensitizations in the CNS.  Things like spontaneous nerve firing and nerve cell damage are factors with both.  I don't know what if anything the parallel means, but it might someday lead to help with one problem due to a solution for the other.  For example, anti-convulsants (like Neurontin) and anti-depressants (serotonin effects) have been used with chronic pain and tinnitus.