Stress and "posture" are certainly big contributors. Any kind of pressure on the veins and nerves around the ear can cause tinnitus, which includes the muscles in your neck, many of which attach to your shoulders. Sitting at a desk all day, or looking down at a phone, is probably a big contributing factor for many of us.

Stress can also cause us to subconsciously clench our jaws, which again can contribute.

Feeling stressed or fatigued certainly lowers my mental tolerance for annoying bullshit like tinnitus.