Hello Am A 24 Year Old African American And My

Hello am a 24 year old African American and my hair used to be very thick and long. But at age 15 I started noticing a tiny bald spot at the back of my hair and now that I am 24 it seems like it is spreading. Now my hair itches so much when I braid my hair so I have cut my hair several times and even stopped braiding it but it seems nothing is helping and I have tried all types of shampoo but nothing is working for me. Now that the thinking patch is spreading am beginning to get scared cause the places of my scalp where the thinning and itching is happening that place seems to never grow it's just short and light but my hair does not fall out. Please I need your help if you can recommend anything please let me know immediately thank you.