Yellow build up on shed hair root?

Can anyone tell me why I get an ache here and there in my scalp and when I pull test the spots, the shed hairs have yellow build up around the bulb? I've been to so many derms and they all say my scalp looks fine, yet I underwent a huge shed in November accompanied with scalp pain and patchy Hairloss. My hairline is deteriorating now and I've been on fin 1yr and 8 months..

Does dutasteride help with sebum since type 1 dht is found more in the follicles?