What you described xcrusher is exactly what Androgenetic Alopecia is.
Since you're only using Nizoral to treat your hair loss and is helpful at doing so, it really won't do much to put a stop to the underlying cause of Androgenetic Alopecia, which is DHT. You will need to get on a 5-AR inhibitor such as Dutasteride or Finasteride, those two medications are strong at fighting Androgenetic Alopecia and have been shown to do so.
About the itching, using Nizoral is not the best shampoo to use to treat Androgenetic Alopecia. The itching is most likely caused by the sodium laureth sulfate in Nizoral, and can actually cause irritation since that cleansing agent itself is an inflammatory compound. I recommend to use Regenepure DR, it is currently the only 1% Ketoconazole shampoo out there that's fit for daily use. Regenepure DR is also sulfate free and has water and aloe vera gel as its two main base ingredients, so it's soothing to the scalp.
About your hair thinning, it's caused by DHT, a strong androgen. Like I previously stated, you'll need to get on a 5-AR inhibitor such as Dutasteride or Finasteride. Getting on either of those two stops the cause of Androgenetic Alopecia.