Thelma-Louise

I wouldn't say its normal, but in regards to tmj it can happen when the c-spine and/or lower jaw is not stable or is shifting which can result in compression of nerves, compromise c-spine alignment or restrict muscle function. By tense neck I assume you mean the muscles in this area and of those shared with the jaw tighten up or contract or are in spasm - if so, keep in mind that it may also be that the eustachion tubes of the ears may also be affected by this thus affecting the equilibrium ergo the dizziness.